Posterize Image guide
Reduce an image to a smaller set of color levels for graphic, print-preview, and stylized effects.
What this tool does
The Posterize Image tool limits how many values each red, green, and blue color channel can use. With two levels, each channel can be only its minimum or maximum value. Higher settings add evenly spaced steps between those endpoints. The combined channels can still produce multiple colors, but smooth gradients become visible color bands and subtle tonal variations are simplified.
Posterization can help preview a limited-tone design, create a bold graphic look, or reveal where gradients may band under aggressive color reduction. It preserves the source width, height, and pixel transparency. The operation is applied uniformly to the whole decoded image.
This tool does not find a globally optimal palette, perform vector tracing, reduce the file to an exact number of total colors, or apply dithering between bands. “Four levels” means four possible values per RGB channel, not four colors in the complete image. For indexed palette control or print separation, use specialist image software and confirm the required color space.
How to use it
- Select a JPG, PNG, or WebP image up to 25 MB for color-level reduction.
- Choose the number of levels per color channel.
- Use a low value for broad blocks of color or a higher value for a gentler effect.
- Select Posterize image to create the export.
- Download the result and inspect gradients, faces, and fine texture.
Try four to six levels first. Very low settings can remove facial detail and create abrupt edges. If the image already contains heavy JPEG artifacts, those blocks may become more obvious after posterization.
Benefits
- Provides a clear, repeatable level control
- Quantizes RGB channels without changing image dimensions
- Keeps transparent pixels transparent in supported formats
- Creates a usable downloadable image rather than a visual preview only
- Runs within a safe decoded-pixel limit
- Keeps the file on the current device
Export and interpretation notes
Canvas export re-encodes the pixels and may remove embedded metadata or color profiles. PNG preserves the new pixel values without additional lossy compression. JPG and WebP exports may differ slightly because their encoders can introduce compression changes. Posterization is a creative transformation; it does not prove that a source has a limited palette or predict a printer’s exact output.