What browser-based image tools can do
Modern browsers ship a complete image pipeline. Canvas and OffscreenCanvas decode JPEG, PNG, WebP, AVIF, GIF and BMP natively; WebAssembly fills in the rest — TIFF, ICO and AVIF encoding. That is everything a conversion, a resize, a crop or a quality-targeted compression needs, which means none of it requires a server. The tools here use that pipeline directly: the file is read into memory, worked on by a Web Worker so the page stays responsive, and handed back to you as a download.
The practical difference shows up on large batches. There is no upload wait, no queue behind other people’s files, no daily cap, and no maximum file size beyond what your own device can hold in memory. Drop thirty photos in and the only limit is how fast your CPU encodes them.
Choosing the right tool for the job
If a form is rejecting your photo, the constraint is usually one of three things. A file-size cap in kilobytes calls for the compress-to-exact-size tool, which searches for the JPEG quality that lands just under your target instead of making you guess. A pixel-dimension or aspect-ratio requirement calls for the resizer, or the passport photo maker when the spec is given in millimetres. A format complaint — "JPG or PNG only" — calls for the converter, and specifically the HEIC route if the photo came off an iPhone.
Scanned documents are the fourth case: when you need the words rather than the picture, the image-to-text tool runs optical character recognition locally, using language data hosted on this site rather than a cloud OCR API.
Quality, formats and what actually gets lost
JPEG and WebP are lossy: every save discards detail, so repeated round-trips degrade an image even when nothing visibly changes at first. PNG is lossless but large, which is why it cannot hit an exact kilobyte target — its encoder ignores quality settings entirely. WebP and AVIF usually beat JPEG by a wide margin at the same visual quality, and both are supported everywhere that matters in 2026, so they are the better default for anything going on the web rather than into a government portal.
Where a conversion can be done without re-encoding, these tools do exactly that — renaming a JFIF file to JPG, for instance, copies the bytes rather than degrading them.