This page opens with the output set to PNG and 256 colors, so every image you drop, including JPG and WebP files, comes out as a PNG. This is the right choice for screenshots, logos, icons, charts and diagrams: anything with flat color and sharp edges.
How the colors are reduced
Every pixel of a truecolor PNG stores its own red, green and blue value, and a PNG with transparency adds a fourth. A palette PNG instead stores up to 256 colors once and gives each pixel a one-byte index into that list. The tool picks the palette in two steps: it splits the image’s colors into groups where they differ most (median cut), then moves each palette color to the average of the pixels it stands for (k-means). Each pixel then gets its nearest palette color, and the small rounding error is passed on to the pixels next to it (Floyd–Steinberg dithering), so gradients and shadows don’t turn into stripes.
The image is then compressed with the same zlib method every PNG uses. On screenshots and charts, the file usually shrinks by more than half.
When fewer colors work
Choose a smaller palette under PNG colors for simpler graphics: 64 or 32 colors is often plenty for a logo or an icon, and saves more. If an image already has fewer colors than you choose, it is stored exactly, so nothing is lost; the row then says “lossless”. To keep every color of a truecolor image, choose All (lossless); fully opaque and fully transparent pixels then stay exactly as they were.
Screenshots and text
Text in screenshots is the one place where JPG struggles: the smooth letters of a UI pick up gray halos and blocks. A 256-color PNG keeps the letters crisp at a similar or smaller size. If your screenshot is mostly a photo, JPG or WebP will still win; compare the sizes in the list and pick the smaller.
When a PNG must be a certain size
If a site limits the file size, switch to the Target size tab. For a PNG, the tool first tries the image losslessly, then with fewer colors: down to 8 for screenshots and graphics, as long as the colors stay true, and down to 64 for photos. Only then does it reduce the pixels.
The settings on this page
| Mode | Quality |
|---|---|
| Quality | 256 colors |
| Format | PNG |
| Maximum size | Original dimensions |
| Metadata | Removed (EXIF, GPS location) |
Every setting can be changed in the tool above; the page only chooses where it starts.