Compare
Weigh WebP and AVIF on this photo
One file, two encodes, same quality and max width. If this device cannot write AVIF, the second column is JPG. Shift will not mint a fake .avif.
Drop one photo
One file. Two encodes. Same quality. The bytes never leave this tab.
Same knobs on both encodes
Why this is not the lecture page
WebP vs AVIF is the theory: support, size, the probe, when to ship a picture tag. This URL is the scale. You drop the photo you actually have. Shift runs convertImage twice with the same quality and optional max width, then puts the bytes in a table. A 24-megapixel JPEG that “should” prefer AVIF sometimes does not, at 85%, on this device. Believe the table.
What happens when AVIF encode is no
The homepage disables the AVIF button. Compare does not invent a third codec and does not rename a JPEG. The pair becomes WebP versus JPG so you still see two real files. That is the honest fallback, not a paywall. Batch convert of one codec still lives on the converter.
What this page will not do
It will not hang a second converter on JPG to WebP — that URL is an article. It will not add SVG or ICO tools. It will not decode HEIC. It will not target a byte budget (that is a different product). It does not upload the photo.