JPEG has been the standard photograph format since 1992. It is lossy: it discards the detail the eye is least likely to notice, which makes a photograph roughly twenty times smaller than a lossless format would. Every save discards a little more, so repeatedly opening and re-saving the same JPEG degrades it.
A JPEG is one flat, opaque picture — no transparency and no layers. Use it for photographs. For hard edges, flat color or text, PNG or WebP give a better result at the same file size.
| Feature | Details |
|---|---|
| Precision | Read: 8-bit, 12-bit and 16-bit |
| Color models | Grayscale, RGB and CMYK |
| Coding modes | Read: baseline, progressive, arithmetic and lossless JPEG |
| Color profiles | Read and written as an embedded ICC profile |
| Metadata | Read: EXIF, IPTC, XMP and the embedded thumbnail |
| Export | Baseline or progressive, with a quality setting |
These are properties of JPEG itself. No program can do better with a .jpg file.
| Limitation | Result |
|---|---|
| Transparency | The format has none. Transparent areas are flattened on export — use PNG, WebP or JPEG XL to keep them |
| Layers | JPEG holds one flat image, so export writes the flattened picture |
| Repeated saving | Each save is a fresh lossy encode. Edit in a layered document and export a JPEG at the end rather than re-saving one over and over |
These are gaps on our side, not the format's.
| Limitation | Result |
|---|---|
| Export precision | 8-bit, though the format allows 12 and 16 and both are read. A higher-precision document is reduced on the way out |
| Arithmetic coding | Read but not written. It is a little denser than the usual Huffman coding and much less widely supported, so export always writes Huffman |
Quality sets how much detail is kept. Higher means more detail and a larger file. The useful range for photographs is roughly 75 to 95; above that the file grows much faster than the picture improves.
Quality also decides how color is stored. Below 90, color detail is recorded at half resolution in each direction — the eye barely notices on a photograph, and it saves a lot of space. At 90 and above, color is kept at full resolution, which matters for anything with saturated edges, colored text or fine red detail.
Progressive writes the same picture as several passes, so it appears blurry and sharpens as it loads. It decodes to identical pixels and is usually slightly smaller.
ICC Profile embeds the document's color profile so other programs show the same colors.