PNG was designed in 1995 as a free replacement for GIF, and set out to fix that format's shortcomings: 24-bit color instead of a 256-entry palette, a true alpha channel instead of one invisible palette entry, and Deflate compression instead of the patented LZW. It is lossless — what you save is what you reopen, exactly.
That makes it the right choice for anything with hard edges or flat color: screenshots, line art, pixel art, logos, and any picture that has to keep a soft transparent edge. For photographs it is simply large, which is what JPEG, WebP and JPEG XL exist for.
| Feature | Details |
|---|---|
| Bit depths | Read: 1, 2, 4, 8 and 16 bits per channel. Written: 8 or 16, taken from the document or chosen with the Depth option, or a 256-color palette with per-entry alpha |
| Color types | Grayscale, RGB, indexed, grayscale with alpha, RGBA |
| Transparency | Full 8- or 16-bit alpha, so soft edges stay soft |
| Interlacing | Read: Adam7, the seven-pass ordering that shows a coarse picture first |
| Color profiles | Read and written as an embedded ICC profile |
| Text and metadata | Read: the text chunks, plus gamma, chromaticities and sRGB tagging |
| Fireworks documents | A PNG saved by Adobe Fireworks opens as its layers, not as one flat picture |
| Export | Still PNG, and APNG for an animated document, at 8 or 16 bits per channel |
These are properties of PNG itself. No program can do better with a .png file.
| Limitation | Result |
|---|---|
| Layers | PNG holds one flat image, so export writes the flattened picture |
| Color models | Grayscale, RGB and indexed only — there is no CMYK PNG |
| File size | Lossless means large for photographs; that is the trade, not a defect. JPEG, WebP and JPEG XL are the alternatives |
These are gaps on our side, not the format's.
| Limitation | Result |
|---|---|
| Animated PNG on opening | Frames are read but not composited — each one opens as its own sub-image rather than being drawn onto the one before it. Export writes APNG correctly |
Simple transparency (tRNS) | Applied for indexed images only; on grayscale and full-color images the nominated transparent color is read but not made transparent |
| MNG and JNG | Not read. These are separate formats from PNG, not PNG features |
There is no quality setting, because there is no quality to trade: PNG stores every pixel exactly and compression only affects the file size. Transparency is kept whenever the document has any.
ICC Profile embeds the document's color profile so other programs show the same colors. Leave it on unless a specific tool you are feeding chokes on tagged files.
Depth is normally Same as document: an 8-bit document writes 8-bit samples and a 16-bit document writes 16-bit ones. 8-bit RGB and 16-bit RGB force a depth. Palette reduces the picture to an optimized palette of up to 256 colors for the smallest file; transparency is kept per palette entry, so soft edges survive as far as 256 entries allow, and Dithering chooses how missing colors are approximated. With Palette depth, Palette picks the color set — Adaptive for the picture's own best colors, or a fixed uniform, web-safe, grayscale, or classic system palette — and Colors sets how many entries to use.
Choose APNG to write an animated document. It plays in a plain image tag in every current browser, keeps full color and real transparency, and Loop # sets how many times it repeats — 0 for forever.