Who already lives in WebP
Teams shipping modern browsers and CDNs. This page is maintenance for that pipeline, not a lecture to convert everything immediately. Keeping PNG or WebP with alpha may cost more kilobytes than an opaque JPEG of the same pixels. Preview against both light and dark backgrounds when edges or transparency may change after encoding. Width and height on the result card update whenever the engine changes dimensions.
Re-encoding tradeoffs
Additional WebP compression can soften detail. Preview product edges and text overlays carefully. If format and size rules conflict, solve format first with a converter, then return for kilobytes. Open the download once before you close the tab. When format or pixel rules sit outside this page, finish those steps on the related tools linked nearby.
When conversion tools are better first steps
If your master is JPG or PNG, convert first, then compress WebP derivatives as needed. High-contrast badge lettering survives better than thin scripts at tight caps. Avoid screenshotting the preview pane, download the generated file instead. Temporary processing is not archival storage, save the download you intend to submit.
Performance mindset
Smaller bytes help LCP, but absurdly tiny images with huge dimensions still decode slowly. Pair size work with sensible pixels. Desktop property panels may round differently than portal checks, trust the on-page measured bytes. Save with a simple name and a single extension before you upload again. Portals care about clearing the limit more than hitting a precise byte total.
Download integrity
The file you download is the measured result. Use it in your deploy folder rather than re-exporting blindly from another app. Families, product variants, and localized banners compress differently with identical settings. If rejection continues, re-read the help text for a second hidden rule. Temporary processing is not archival storage, save the download you intend to submit.
Caching and versioning WebP files
When you replace a WebP in production, bump the cache-busting query or filename so browsers do not keep an older heavier asset. Measure the new file after deploy, not only in this preview. If a reverse proxy strips query strings, change the object key instead. Flattening alpha onto JPG removes soft edges; check logos carefully after conversion. Evenly lit, face-forward crops usually survive tighter budgets better than wide scenes. Temporary processing is not archival storage, save the download you intend to submit.
Before you deploy the WebP
Deploy the WebP after confirming your stack can serve it. Keep JPG fallbacks where old clients still matter. Transparent corners look fine on light themes and expose matte boxes on dark UI, preview both. If rejection continues, re-read the help text for a second hidden rule. When format or pixel rules sit outside this page, finish those steps on the related tools linked nearby.
How this compressor behaves
This is a quality-first pass at the original pixel size. It does not chase a kilobyte ceiling. On an already-tight JPG, the rewrite can stay similar or grow. Use a target-size tool when a form names a hard limit.
Shared test method
This tool uses the same upload validation, processing, and download path described on How we test. Representative tools were last verified on 5 October 2026. Individual pages only show a PASS card when that slug was in the measured sample.
When a general pass is the wrong tool
If a portal names 50KB, 100KB, or 200KB, use the matching target tool. Quality-first compression is for reducing obvious bulk, not for guaranteed ceilings. Our measured set of already-encoded web JPEGs often grew after a high-quality rewrite.
Technical reference
WebP is a Google image format for lossy and lossless still images, with optional animation and alpha. Official documentation: WebP on Google Developers.
Related research
On already-encoded web photographs, a quality-first JPG rewrite often increased bytes. That is a measured finding, not a slogan: JPG compression quality test.
Frequently asked questions
Is WebP supported in all browsers you care about?
Most modern browsers yes. If you must support ancient clients, keep a JPG fallback strategy outside this tool. Phone galleries sometimes re-encode on share, upload the downloaded file directly when you can.
Can I compress animated WebP?
This workflow focuses on typical still assets. Animation-heavy files may not be the right input. Phone galleries sometimes re-encode on share, upload the downloaded file directly when you can.
Does this create JPG instead?
No. Stay on WebP here. Use converters when you need another format for compatibility. Slightly under a maximum is usually acceptable; slightly over is a common silent failure.
How do I judge quality?
Preview at 1x and 2x zoom on a phone. Soft logos fail that test quickly. Judge the downloaded file itself, not memory of how the preview looked a minute earlier.
Any fake size claims?
No. Displayed sizes come from the generated file length after processing completes. Slightly under a maximum is usually acceptable; slightly over is a common silent failure.