PNG to WebP: Smaller Files, Transparency Intact

PageSpeed Insights flagged your images and pointed straight at the PNGs. It's right to. A page carrying eight PNG screenshots is hauling several megabytes that don't need to be there, and WebP is the least painful way to fix it.

Unlike most format conversions, this one doesn't force an awkward trade. You get smaller files and you keep transparency, which is the pair of things people usually have to choose between.

What you gain

• Roughly 25 to 35 percent smaller than the PNG at comparable visual quality. On photographic PNGs the gap is far wider than that, sometimes 80 percent or more, because PNG is genuinely poor at storing photographs.
• Transparency survives. WebP has a full alpha channel, so a cutout logo stays a cutout logo.
• Around 97 percent of browsers in use today display WebP, which in practice means everything your visitors are running.
• It handles both kinds of image. WebP does photographs and flat graphics competently, which is unusual. JPG is hopeless at flat graphics and PNG is hopeless at photographs.

How to convert PNG to WebP

1. Open the Image Converter.
2. Drop in your PNGs. A whole folder is fine, there's no limit on batch size.
3. Set the output format to WEBP.
4. Adjust quality. 75 to 85 covers photographs comfortably. For flat graphics and anything with text in it, push to 90 or higher, for a reason worth reading below.
5. Convert, then download everything as a ZIP.

Conversion happens on your own machine inside the browser tab, so a hundred files take as long as your laptop needs and not a second longer waiting in someone's server queue.

The gotcha nobody puts on these pages

Lossy WebP stores brightness detail at full resolution but color detail at half resolution. It's a shortcut borrowed from video compression, and on photographs it's completely invisible, because your eyes are much sharper at brightness than at color.

On flat graphics it can show. Saturated red or blue text on a white background is the classic case: the edges pick up a faint smear or halo that wasn't in the PNG. Same story with thin colored lines in a chart.

The fix is easy. Raise the quality slider for graphics, then open the result at 100 percent zoom and look at the sharpest colored edge in the image. If it's clean, ship it. If it's fuzzy, either go higher or leave that particular file as a PNG.

Tiny images sometimes get bigger

Every WebP file carries a small amount of structural overhead. On a 900 KB photograph that's a rounding error. On a 2 KB interface icon it can outweigh the compression entirely and hand you a larger file than you started with. Icons, sprites, and simple UI graphics are usually better left as PNG, or better still redrawn as SVG.

Why you'd still keep the PNG

Keep the PNG as your master copy. It's lossless, and lossy WebP is not. Once you delete the PNG you can never get back to a clean original, only to a copy of a copy. Storage is cheap and regret isn't.

Beyond that, a few destinations still argue for PNG specifically. Print workflows and older desktop publishing software often want PNG or TIFF. Some marketplace and job portal uploaders reject WebP outright. A handful of email clients still won't render it, and a broken image in a newsletter is worse than a heavier one.

For everything that lives on a website, though, WebP is the sensible default in 2026.

Or go one step further

AVIF compresses harder still, usually another 20 percent below WebP, with browser support around 92 percent. It also encodes considerably slower, which matters when you're processing hundreds of files. Converting to AVIF is worth it for hero images and product photos. For a big batch on a deadline, WebP remains the pragmatic answer.