Why convert PNG to WebP
WebP is an image format built for the web: for photographs and screenshots it typically comes out 25-35% smaller than the equivalent PNG, and unlike JPG it keeps alpha transparency, so logos and UI elements with see-through backgrounds survive the switch. Every current browser — Chrome, Firefox, Edge, and Safari — displays WebP natively, which is why site-speed tools like Lighthouse routinely flag large PNGs and suggest it. Smaller images mean faster page loads, lower bandwidth use, and better Core Web Vitals scores. One honest caveat: small flat-color graphics are already efficient as PNG, so the savings there can be modest.
How the browser does the work
This tool doesn't ship a compression library. It decodes each PNG, draws it onto a canvas, and asks the browser's own built-in WebP encoder to re-encode it. Because that encoder is native code rather than JavaScript, conversion stays quick even for large screenshots. You can queue a whole batch of PNGs, watch each one report its new file size as it finishes, and download the results individually or bundled into a single ZIP.
Nothing gets uploaded
Screenshots are among the most common images people convert, and they often show more than intended: private dashboards, inboxes, names, account numbers. Since the entire re-encode happens inside your browser tab, the image data never travels over the network — no server receives, stores, or logs your files. Close the tab and nothing persists anywhere except your own downloads folder.