Image pixel difference checker
Highlight changed pixels with a configurable threshold.
איך להשתמש ב-Image pixel difference checker
The Image pixel difference checker compares two images with identical pixel dimensions and returns a PNG map where changed pixels are highlighted in a strong pink and unchanged pixels appear light gray. It also reports how many pixels changed and what percentage of the image that is. A threshold from 0 to 255 controls how large a change must be to count.
- Choose a source file. If the tool accepts multiple files, arrange them in the order you want.
- Set difference threshold (0–255).
- Run image pixel difference checker, review the output, then use the available copy or download controls.
יכולות הכלי
Highlight changed pixels with a configurable threshold.
- Difference threshold (0–255)
- Range: 0 to 255
מגבלות ועיבוד
Images use the existing 32-megapixel canvas bound. Up to 100 source images are allowed where supported. Pasted HTML is bounded to 200,000 characters; Mermaid diagrams to 20,000 characters and 300 lines. SVG and PNG generation require a browser.
שאלות נפוצות
How does the difference threshold work?
For each pixel, the checker finds the largest absolute difference across the red, green, blue and alpha channels. A pixel is marked as changed only when that difference is greater than the threshold. 0 flags any change at all, while the default of 20 ignores small compression noise.
Why do my images need the same dimensions?
Pixels are compared one to one at the same coordinates, so both images must have exactly the same width and height. If they differ, the tool returns an error rather than resizing, because scaling would itself change pixels.
Can I use this for visual regression testing of screenshots?
Yes, as a manual check. Export two screenshots at the same size, compare them and review the highlighted map and the changed-pixel percentage. Raising the threshold helps ignore antialiasing differences, but the result is a visual report rather than a pass or fail test.
Where is my input processed?
This operation processes its source in your browser. Copy and download are explicit actions; source input is not saved in an account or history.
What are the input limits?
Images use the existing 32-megapixel canvas bound. Up to 100 source images are allowed where supported. Pasted HTML is bounded to 200,000 characters; Mermaid diagrams to 20,000 characters and 300 lines. SVG and PNG generation require a browser.