Frequently asked questions.

No. All compression happens entirely within your web browser using modern web APIs. Your files never leave your device, ensuring 100% privacy. ZeroPNG does not have any server-side image processing infrastructure, everything runs locally on your computer.

No. ZeroPNG can only access the files you explicitly select or drag-and-drop into the application. It runs in a sandboxed browser environment and has no access to your file system beyond what you choose to share.

The only data ZeroPNG stores locally is your theme preference (dark/light mode) in your browser's localStorage. No images, file names, or usage data are ever stored. You can clear this at any time through your browser settings.

Yes. Because all processing happens entirely inside your browser and your files never touch any server, ZeroPNG is safe to use with sensitive, confidential, or medical images. There is no transmission, no logging, and no storage on our end, making it suitable even in privacy-regulated environments.

Simply drag and drop your images onto the drop zone, or click it to browse for files. Adjust the quality slider and output format if needed, then hit "Compress All." You can download files individually or as a ZIP archive.

Input formats: PNG, JPEG, WebP, AVIF, and GIF.
Output formats: PNG, JPEG, WebP, and AVIF. You can also keep the original format while still reducing file size.

For web viewing, WebP or AVIF offer the best compression. If you need maximum compatibility, stick with JPEG (for photos) or PNG (for graphics with transparency). Use "Keep Original" to reduce size without changing the format.

The quality slider (10-100%) controls how aggressively the image is compressed. Higher values retain more detail but produce larger files. For most images, 70-80% offers an excellent balance between quality and file size with virtually no visible difference.

Yes! Use the "Max Width" dropdown to cap the output width. Options include 4K (3840px), 1920px, 1280px, 800px, and 400px. The aspect ratio is always preserved. Select "No Resize" to keep the original dimensions.

There is no hard limit. ZeroPNG uses your computer's processing power, so you can compress hundreds of images at once. Processing speed depends on your device's capabilities and the size of the images.

Yes! Simply copy an image (e.g., a screenshot) and paste it directly onto the page using Ctrl+V / Cmd+V. ZeroPNG will add it to the queue automatically.

Yes. ZeroPNG works on modern mobile browsers including Safari on iOS and Chrome on Android. For the best experience, use the desktop version, the tools are fully functional on mobile but the two-column layout is optimised for larger screens.

After processing, click the "Download All" or "Download ZIP" button in the toolbar. ZeroPNG bundles all your output files into a single ZIP archive that downloads in one click, no need to save them individually.

Because the server doesn't process the images (your computer does all the work!), our hosting costs are essentially zero. There are no artificial limits, no premium tiers, and no hidden fees.

Yes! Once you load the site for the first time, it installs a Service Worker that caches the entire app. You can disconnect from the internet and continue compressing images. Everything works the same as online.

We recommend keeping individual files under 20 MB to ensure smooth processing without crashing your browser tab. However, there are no hard server limits since everything is processed locally on your device.

ZeroPNG uses color quantization to reduce the number of colors in a PNG image (similar to TinyPNG). A 24-bit PNG with millions of colors is reduced to an 8-bit palette of 256 colors or fewer, achieving 60-80% reduction while maintaining visual quality.

No, your original files are never altered. ZeroPNG creates new, optimized versions of your images that you can download individually or together as a single ZIP file. Your originals remain completely untouched.

ZeroPNG works on all modern browsers including Chrome, Firefox, Safari, Edge, and Opera. For the best experience and full format support (especially AVIF), we recommend using the latest version of Chrome or Edge.

AVIF uses the AV1 codec which is computationally intensive. The browser's built-in Canvas API handles AVIF encoding, and it requires significantly more processing time than JPEG or WebP. The trade-off is that AVIF produces the smallest files of any format.

All three tools produce high-quality compressed images. The key difference is privacy: TinyPNG uploads your files to its servers for processing, and Squoosh is Google-backed. ZeroPNG processes everything locally in your browser using the same professional codecs, libpng, libjpeg-turbo, libavif, libwebp, so your files never leave your device. ZeroPNG also offers more tools in one place: conversion, cropping, EXIF removal, watermarking, and web analysis alongside compression.

WebAssembly (WASM) is a binary instruction format that runs at near-native speed inside the browser. It lets us compile the same C-based codecs used in professional desktop software, like libpng and libjpeg-turbo, and run them directly in your tab. The result: server-grade compression quality with zero uploads, because your device's CPU does all the work.

Typical reductions are 60–80% for PNG and 50-70% for JPEG, depending on image content and quality settings. Photos with large areas of solid color compress best. The average across all files processed on ZeroPNG is around 72%.

Lossless compression (PNG) discards no visual data, every pixel is mathematically identical to the original. Lossy compression (JPEG, WebP, AVIF) trades a small, often imperceptible amount of quality for dramatically smaller files. ZeroPNG's quality slider lets you control exactly how aggressive lossy compression is.

PNG compression uses color quantization: a 24-bit image with millions of colors is reduced to an 8-bit palette of up to 256 carefully chosen colors. The human eye can rarely tell the difference, but the file size drops by 60–80% because far fewer bits are needed to describe each pixel.

Compression alone does not change dimensions. Pixel dimensions stay the same unless you also use the "Max Width" resize option. Reducing dimensions is often the single most effective way to shrink file size, since halving the width and height reduces pixel count by 75%.

Yes. Drop or select as many files as you like, there is no batch limit. All images are compressed simultaneously using your browser's processing power. Download them individually or grab all output files in a single ZIP.

Yes, every lossy re-encode introduces a small amount of additional quality loss. If you must re-compress a JPEG, use a high quality setting (85–95%) to minimise the degradation. For archiving, always keep the original uncompressed or lossless copy.

Use ZeroPNG's free Image Converter to convert between PNG, JPG, WebP, and AVIF formats. Simply drop your images, choose your target format from the dropdown, adjust quality if needed, and click "Convert All." All conversion happens in your browser, no uploads required.

WebP is the best format for converting PNG images for web use. WebP produces files 25-35% smaller than PNG while supporting transparency. It's supported by 97%+ of browsers in 2026. For maximum compression, try AVIF which offers even smaller files (~50% smaller than JPEG) but has slightly less browser support (~92%).

Yes, when you convert JPG to PNG using ZeroPNG's converter, the output is lossless PNG. However, note that since JPG is already a lossy format, converting to PNG won't recover quality lost during the original JPEG compression. The PNG output will be a lossless copy of the JPEG data, typically in a larger file size.

WebP offers good compression with 97%+ browser support, it's the safest modern format choice. AVIF offers even better compression (up to 50% smaller than JPEG) but has slower encoding, slightly less browser support (~92%), and can struggle with very detailed textures. For most users, WebP is the recommended choice; use AVIF when maximum compression matters most.

Absolutely. Drop or select as many images as you need, there's no limit. All files are converted simultaneously using your browser's processing power. Download them individually or grab everything as a single ZIP file.

Yes, when converting to formats that support transparency, PNG, WebP, and AVIF all preserve alpha channels. If you convert to JPEG, transparent areas will be filled with a white background since JPEG doesn't support transparency.

Use ZeroPNG's free HEIC to JPG Converter. Simply drag and drop your iPhone HEIC photos, they auto-convert to high-quality JPG instantly. No signup, no watermarks, no file limits. All conversion happens in your browser so your photos are never uploaded to any server.

HEIC (High Efficiency Image Container) is Apple's default photo format on iPhone and iPad since iOS 11. It uses the HEVC codec to store photos ~50% smaller than JPEG. Most Windows PCs, Android devices, Chrome, Firefox, and many websites can't open HEIC files natively, that's why a HEIC to JPG converter is essential.

For iPhone photos, JPG is recommended - it produces much smaller files with excellent quality, ideal for sharing via email, social media, and web. Choose PNG only if you need perfect lossless quality. HEIC to JPG at 92% quality is the sweet spot for most users.

Yes, ZeroPNG's HEIC converter is the most private option available. Unlike other online converters that upload your photos to remote servers, ZeroPNG processes everything 100% in your browser using client-side JavaScript. Your iPhone photos never leave your device.

Windows doesn't natively support HEIC files. You can either install the HEIF Image Extensions from the Microsoft Store (may require a paid HEVC codec), or use ZeroPNG's free online HEIC to JPG converter to instantly convert your HEIC files to universally compatible JPG format.

On your iPhone, go to Settings → Camera → Formats and select "Most Compatible" instead of "High Efficiency." This makes your iPhone save new photos as JPEG. For existing HEIC photos on your camera roll, use ZeroPNG's HEIC converter to batch convert them to JPG.

Use ZeroPNG's free Image Cropper tool. Simply upload your image, adjust the selection box to your desired area, and click "Crop Image." You can then download the perfectly cropped version instantly. Everything happens 100% in your browser for total privacy.

ZeroPNG includes built-in presets for popular platforms: Square (1:1) for Instagram posts, Portrait (4:5) for feed photos, Stories/Reels (9:16) for vertical content, and Landscape (16:9) for YouTube or Facebook covers.

Yes! You can manually enter specific Width and Height in pixels, or choose "Custom" from the aspect ratio menu to free-form drag the crop box to any size. The dimensions update in real-time as you resize.

No. ZeroPNG's Image Cropper uses the high-resolution source data to create your crop. Unless you also choose to resize the output to a smaller resolution, your cropped image will maintain the same pixel quality as the original photo.

Selecting any preset (like 1:1 or 16:9) automatically locks the aspect ratio. This ensures that no matter how you resize the crop box, it maintains the correct proportions. Choose "Custom" if you want to unlock it and resize freely.

Simply drop your image into ZeroPNG's Image Watermark tool, enter your text or upload a logo, adjust the position, size, and opacity, then click "Apply & Download." No sign-up, no uploads, everything runs in your browser.

Yes! Change the watermark type to "Logo (Image)" and upload your specific PNG or SVG logo. You can then scale and position it exactly where you want on the base image.

No. ZeroPNG's watermarking tool processes your images at their original quality. You can also choose your preferred output format (JPEG, PNG, or WebP) when downloading.

Currently, the watermarking tool processes one image at a time to ensure precise placement and preview. However, since it runs entirely in your browser, there's no limit to how many images you can process sequentially.

Yes. ZeroPNG's watermark tool lets you choose from nine placement positions: top-left, top-center, top-right, middle-left, center, middle-right, bottom-left, bottom-center, and bottom-right. You can also adjust the margin offset so the watermark sits exactly where you want.

You can upload a PNG or SVG file as your logo watermark. PNG is recommended for logos with transparency. SVG is ideal if you want your watermark to scale crisply at any size without pixelation.

EXIF (Exchangeable Image File Format) data is metadata embedded in every photo your camera or phone takes. It can include GPS coordinates, camera make and model, serial numbers, timestamps, and lens information. Removing it before posting publicly prevents location tracking and device fingerprinting.

No. EXIF metadata is entirely separate from the visual pixel data. Stripping it produces a visually identical image, and usually a slightly smaller file size since the metadata bytes are removed.

Yes. Drop as many images as you need into the EXIF Stripper and ZeroPNG removes metadata from all of them in a single pass. Download them individually or as a ZIP, no batch size limit.

ZeroPNG strips GPS location, camera make and model, serial numbers, timestamps, copyright notices, software tags, and all other embedded IPTC and XMP segments. You can preview the metadata found in each file before downloading the cleaned version.

Base64 lets you embed images directly into HTML, CSS, or JavaScript as a plain text string. This eliminates an extra HTTP request for the image, which is useful for small icons, inline email templates, or critical above-the-fold images you want to load instantly.

Yes, Base64 encoding adds roughly 33% overhead compared to the binary file. For this reason it's best suited for small images such as icons and thumbnails. For large photos, a standard <img> tag with a compressed WebP file will always outperform an inline Base64 string.

You get three ready-to-use snippets: the raw Base64 string, a complete <img src="data:..."> HTML tag, and a CSS background-image: url(...) declaration, all formatted to paste directly into your code.

Yes, entirely. Your image is read locally by the browser's FileReader API and encoded client-side. No data is sent to any server at any point.

The Watermark tool is designed for single images with a live preview. Bulk Watermark lets you drop dozens of images at once, apply the same text or logo watermark to all of them, and download everything as a ZIP, ideal for product photography, event photos, or content batches.

Yes. Switch the watermark type to "Logo (Image)" and upload your PNG or SVG logo. The same logo, position, size, and opacity settings are applied consistently to every image in the batch.

There is no hard limit. ZeroPNG processes your images locally in the browser, so throughput depends on your device's memory and CPU. For very large batches (hundreds of high-resolution images) it is good practice to process in groups of 50–100 to avoid browser tab memory pressure.

You can choose from nine placement positions, corners, edges, and center, plus an adjustable margin offset. The position is applied uniformly to all images in the batch. For per-image placement control, use the single-image Watermark tool instead.

After processing completes, click the "Download ZIP" button. All watermarked images are bundled into a single ZIP archive that downloads in one click. You can also download images individually from the file queue.

You can export watermarked images as JPEG, PNG, or WebP. JPEG is recommended for photos, PNG for images that need transparency, and WebP for the best balance of quality and file size for web use.

SVG is ideal for scalable graphics, but many platforms, social networks, email clients, word processors, and some CMSs, do not support SVG. Converting to PNG or JPG gives you a universally compatible raster image while ZeroPNG's scale options let you export at the resolution you need.

You can export at 1× (native SVG viewport size), 2×, 3×, or 4×. Use 2× for standard HiDPI/Retina screens, 3× or 4× when you need very large raster images, for example print assets or high-resolution social banners.

Yes. The SVG is rendered in the browser's native SVG engine, so colors, gradients, masks, and filters are all faithfully reproduced. Transparency is preserved when exporting to PNG or WebP. JPEG output fills transparent areas with a white background.

The converter captures a static frame (the initial state) of an animated SVG. If you need an animated output, consider exporting as an animated WebP or GIF using a dedicated tool. For a still screenshot of the first frame, the SVG converter works perfectly.

This usually happens when the SVG has no explicit width and height attributes on its root element, only a viewBox. Open the SVG in a text editor and add width and height values that match the viewBox dimensions, then re-upload.

Yes, entirely. The SVG is drawn onto an HTML Canvas element using the browser's built-in rendering engine, then exported as a PNG or JPG. No file is sent to any server at any point.

ZeroPNG runs the popular SVGO (SVG Optimizer) engine directly in your web browser. When you drop an SVG, it parses the XML elements and applies optimization plugins to strip metadata, clean paths, remove empty groups, and reduce precision, all without sending your SVG to any server.

We offer three presets: Default (recommended for standard use, cleans markup safely), Aggressive (removes width/height to force viewBox responsiveness, aggressively simplifies paths), and Prettify (optimizes the SVG structure but formats output XML with neat indentation for reading).

Yes, entirely. Like all ZeroPNG tools, the SVG Optimizer runs 100% locally on your computer. Your vector files are processed inside your browser's sandbox and are never uploaded or stored.

In rare cases, aggressive minification can alter complex gradients, masks, or path details. If you notice any rendering issues, you can preview the original vs optimized versions using our visual slider and toggle specific optimization plugins in the settings panel to preserve those paths.

Yes. You can drop dozens of SVG files at once. All of them will be optimized in parallel using your browser's thread pool. You can then download them individually or as a compiled ZIP archive.

Use ZeroPNG's free Image Resizer. Upload your image, enter the target width and/or height in pixels, and click "Resize." The resized image downloads instantly. All processing happens in your browser, no uploads, no accounts.

Scaling an image down is lossless in terms of the resize operation itself, but you are permanently removing pixel data. For best results, always work from the highest-resolution original and resize down rather than up. Enlarging an image beyond its original size will produce a blurry result because the missing pixels must be interpolated.

Yes. With the "Lock Aspect Ratio" option enabled (the default), entering a width automatically calculates the correct height and vice versa. Disable it only when you need to stretch an image to exact dimensions regardless of distortion.

Resizing scales the entire image to new dimensions, changing all content proportionally. Cropping cuts away parts of the image to isolate a specific region without scaling. Use the Image Cropper when you need to remove edges or produce a specific aspect ratio for social media.

You can save the resized image as JPEG, PNG, or WebP. JPEG is best for photos, PNG for graphics that need transparency, and WebP for the best balance of quality and file size for web use.

There is no hard server limit since everything runs locally in your browser. In practice, very large output dimensions (e.g. 10 000 × 10 000 px) can exceed browser canvas memory limits on lower-end devices. For typical web and print sizes you will not hit any restrictions.

Use ZeroPNG's free Images to PDF tool. Drop your JPG, PNG, or WebP images, arrange them in the order you want, and click "Create PDF." Your PDF downloads instantly. Nothing is uploaded, all conversion happens in your browser.

You can combine JPEG, PNG, WebP, and AVIF images in the same PDF. Each image is placed on its own page at your chosen paper size and orientation.

Yes. You can select from standard paper sizes including A4, Letter, and more, and switch between portrait and landscape orientation. The tool scales each image to fit the chosen page size while preserving its aspect ratio.

Yes. After uploading, drag and drop the thumbnails to arrange the page order before you generate the PDF. You can also remove individual images from the list.

There is no hard limit. Since all processing runs locally, throughput depends on your device's memory. For very large batches of high-resolution images, it is good practice to keep the batch under a few hundred images to avoid browser tab memory pressure.

No. ZeroPNG generates the PDF entirely in your browser using the jsPDF library. Your images never leave your device, making this the safest way to convert confidential or personal photos to PDF.

Use our free Image Vectorizer. Simply drop your PNG or JPG files, adjust path thresholds or colors, and trace it. The tool generates clean SVG vector code inside your browser, with no file uploads.

Raster images use color pixels and lose quality when zoomed. Vector graphics use mathematical paths, allowing them to scale infinitely without pixelation, which is ideal for logos, icons, and illustrations.

No. ZeroPNG traces and vectorizes files entirely client-side using JavaScript tracing engines in your local browser sandbox, ensuring 100% privacy.

You can customize tracing presets (e.g. detailed, posterized, outlines), adjust the color count, path threshold, blur radius, and simplify lines for cleaner vector path markup.

Use our free Censor & Blur tool. Drop your photo, select your redaction type (Blur, Pixelate, or Color Fill), and drag to draw redact boxes over sensitive items. Download the flattened, censored file locally.

No. ZeroPNG overwrites the underlying raw image pixels on the canvas with the redacted data. Once you download the flattened output, the original text is completely lost and cannot be recovered or un-blurred.

Yes! Simply click inside a drawn box to select it. You can drag its corner handles to resize, or drag its center to reposition the redact zone anywhere on the image.

Yes, 100%. All drawing, blurring, and pixelating processes run client-side on your device. Your sensitive files, receipts, or passports never touch a remote server, ensuring complete compliance and privacy.

The Web Image Analyzer scans any public webpage URL and audits every image on it. It checks for oversized files, unoptimised formats, missing dimensions, lazy-loading issues, and flags images that may be harming your Core Web Vitals score.

No. Just enter a public URL. The analyzer fetches the page and inspects its images, nothing from your device is uploaded. It's purely an outbound audit of a live webpage.

No. The analyzer can only audit publicly accessible URLs, the same pages any search engine crawler can reach. Pages behind a login, firewall, or staging domain are not accessible.

The analyzer highlights which images are the largest offenders. Use ZeroPNG's Image Compressor to shrink oversized files, the Image Converter to switch to WebP or AVIF, and ensure images have explicit width/height attributes to prevent layout shift (CLS).

ZeroPNG's AI Background Remover runs a deep-learning segmentation model (RMBG) directly in your browser using ONNX Runtime. The model identifies the subject of your photo and removes the background, outputting a transparent PNG, all without uploading a single pixel.

The AI model excels at portraits, product photos, and objects with clearly defined edges against a contrasting background. Results are typically excellent for people, animals, and isolated objects. Complex scenes with similar foreground and background colors may require manual touchup in a photo editor.

No. The RMBG model weights are downloaded once to your browser and all inference runs locally on your device using WebAssembly and WebGL. Your photos never leave your machine, privacy is guaranteed even for sensitive or personal images.

The AI model file (~170 MB) is downloaded on the first use and cached in your browser. Subsequent runs use the cached model and are much faster. The actual background removal for a typical photo takes only a few seconds once the model is loaded.

The output is always a PNG file with a transparent background (alpha channel). PNG is the only lossless format that supports full transparency. You can then place the subject over any background in a design tool.

Yes. Drop multiple images at once and the tool queues them automatically, processing each image with the same AI model. All results can be downloaded individually or as a ZIP archive.

The AI Photo Restorer runs deep-learning restoration networks directly in your browser using ONNX Runtime. It reconstructs facial details, removes compression noise, and upscales images up to 4×, keeping all processing 100% private.

No. Like other ZeroPNG tools, all AI model execution happens locally on your computer via WebAssembly. Your photos never touch any remote server, ensuring complete confidentiality.

To perform advanced details restoration, your browser downloads the neural network model file (~60-100 MB) once and caches it locally. Subsequent upscale runs are much faster as they run from local cache.

You can upscale images by 2× or 4× their original pixel resolution. The tool cleans up blur and noise artifacts, giving you a sharper and larger image.