WebP compression — Verify the result

Worked example

To verify a compressed WebP, confirm the file type, compare bytes and dimensions, and view it on light and dark backgrounds.

After you press Compress image, the summary line lists the original and the result, for example a 1600 × 900 WebP followed by a 1600 × 900 WebP at a lower weight, and the saved file is named like banner-compress.webp. If the status says the original was kept, the re-encode was not smaller and the file you hold is your source.

Check the format itself. The summary labels the output type, and the extension should be .webp. Open it in a browser tab, which reads the real content type, and confirm it displays. An image viewer that does not know WebP will fail even though the file is fine, so test in the place it will actually be shown.

Inspect the picture at 100 percent. For a cut-out product, look at the edge against a dark backdrop for pale fringes, and for a banner, check gradients and small text for smearing. Confirm it is a still frame, not a clip, since the tool makes a single image.

The mistake to avoid is trusting that a local success means universal support. Upload or place the file in the real destination, such as a CMS media library or an email template, and look at the rendered result there. Note the byte size and the quality value so the same setting can be repeated.

WebP still image

WebP still export

Open the finished file in the application that will display it, since support for WebP varies between tools.