Posterize Image Image
Reduce an image to a handful of color levels for a poster-print look.
Posterize Image is a free online tool that reduce an image to a handful of color levels for a poster-print look. It accepts JPG, PNG, WEBP, GIF, BMP, AVIF and SVG — anything your browser can display. It produces pNG by default.. It runs entirely in your web browser using Canvas 2D, so files are processed on your own device and never uploaded to a server. There is no sign-up, no file size limit imposed by the site, no watermark and no paid tier.
- Price
- Free — no account, no quota, no watermark
- Category
- Image
- Where it runs
- In your browser, on your device
- Files uploaded
- None
- Input
- JPG, PNG, WEBP, GIF, BMP, AVIF and SVG
- Output
- PNG by default
- Technology
- Canvas 2D
- Settings
- 1
- Works offline
- Yes, after the first visit
About Posterize Image
Posterising quantises each channel to a fixed number of evenly spaced levels. At 4 levels per channel you get at most 64 distinct colors, at 8 you get 512. The banding it produces in gradients is the whole point — it is the look of screen-printed posters, where each color needed its own physical pass.
How to use it
- Choose an image, or drag one onto the drop zone.
- Set levels per channel.
- Check the preview, then download. Your original file is never modified.
The one setting
| Setting | What it does | Default |
|---|---|---|
| Levels per channel | Range 2–16. | 4 |
Under the hood
| Runs on | Canvas 2D — does the pixel work |
| Accepts | JPG, PNG, WEBP, GIF, BMP, AVIF and SVG — anything your browser can display |
| Produces | PNG by default |
| Controls | Levels per channel |
Questions
How few levels can I go?
Two levels per channel gives eight colors and a strong graphic-poster look. Below four, photographs stop reading as photographs — which may be exactly what you want.
Which file types can I use?
JPG, PNG, WEBP, GIF, BMP, AVIF and SVG — anything your browser can display. Because decoding is handled by your browser rather than a conversion server, support tracks whatever your browser can already open.
Is there a file size limit?
No imposed limit — there is no server quota to hit. The real ceiling is your device's memory, since the whole file is held in RAM while it is processed. Desktop browsers cope with very large files; phones give up sooner.
What are the limits on levels per channel?
It accepts 2 to 16, starting at 4.