What each format is actually for
JPEG is for photographs and nothing else. It has no alpha channel, and its discrete cosine transform is built for smooth gradients, so it does badly on the hard edges of text and line art. PNG is lossless with alpha: correct for screenshots, logos and anything with sharp edges, and wasteful for photographs. WebP does both jobs, lossy or lossless and always with alpha, and typically lands 25 to 35% under JPEG at matched quality. AVIF goes roughly 20% under WebP again, at a much higher encoding cost.
For the web in 2026 the honest default is WebP: universal support, alpha, and a real saving over both of the formats it replaces. AVIF where the extra 20% matters and you can afford the encode.
The conversions that lose something
Anything to JPEG loses transparency. The transparent pixels have to become a colour, and the default in almost every canvas pipeline is transparent black. That is why a logo converted to JPEG so often comes back with a black box behind it. This page asks which colour, and warns before it happens.
Anything animated becomes a still. A canvas decodes one frame. An animated GIF or WebP converted here keeps its first frame and drops the rest, silently in every other tool and loudly in this one.
Every conversion drops the metadata. EXIF, IPTC, XMP and the colour profile live in the container, not in the pixels, and the container is what a conversion replaces. Usually an improvement, occasionally a surprise: a Display P3 photo converted here comes out untagged and is read as sRGB.
HEIC, and why it fails here
HEIC is what an iPhone shoots by default, and it is decodable in Safari and effectively nowhere else, because the patent position around HEVC kept it out of the other browsers. This page says so instead of failing with a generic error, because it is by far the most common file it cannot open. Decoding it would mean shipping a multi-megabyte WASM decoder that every visitor downloads, which is not a trade this site makes. Setting the iPhone camera to "Most Compatible" produces JPEG at capture time and sidesteps the whole thing.
Common problems
- PNG to JPEG made the file bigger. The source was flat colour, a screenshot or a diagram, which PNG compresses far better than JPEG can. JPEG only wins on photographs.
- The AVIF option is greyed out. This browser has no AVIF encoder. It was checked by encoding a single pixel, not inferred, so the answer is about this browser rather than about AVIF.
- The converted image looks washed out. An embedded colour profile was dropped, and the browser now reads the pixels as sRGB. For wide-gamut photography, convert in an application that carries the profile through.
Frequently asked questions
Does converting reduce quality?
To PNG, never. To JPEG, WebP or AVIF at a lossy quality, yes, and it compounds: each lossy re-encode quantises the previous pass's artefacts as if they were image detail. Always convert from the original file rather than from something this page produced.
Is there a file size limit?
No upload, so no upload limit. The real ceiling is memory: a decoded image is width × height × 4 bytes regardless of the file size on disk.
Can it convert to SVG?
No, and be suspicious of anything that says it can. SVG is vector; turning a photograph into one requires tracing, which invents shapes that were never in the image and usually produces a file larger than the original. The other direction, SVG to PNG, is a real conversion and has its own tool here.
Which format should I actually pick?
WebP for almost everything on the web: universal support, an alpha channel, and typically 25 to 35% under JPEG at matched quality. AVIF where the extra saving justifies a slower encode. PNG for screenshots and line art. JPEG only for photographs going somewhere that accepts nothing newer.