diffimg

Calculate difference between images

$ diffimg [path/to/image1.ext] [path/to/image2.ext] [path/to/output.ext]

diffimg image1 image2 output

diffimg calculates pixel-level differences between two images by comparing corresponding pixels and generating a difference image. Each pixel in the output represents the delta between the input images at that position, making visual changes immediately apparent.
The tool performs per-pixel subtraction or comparison operations, highlighting areas where images differ. This is valuable for visual regression testing in web development, where screenshots of UI components can be compared across code changes to detect unintended visual modifications.
Common use cases include comparing rendered output before and after changes, detecting image manipulation, and automated quality assurance for graphics pipelines. The tool supports multiple image formats including PNG, JPEG, GIF, and PostScript.

image1

First input image

Second input image

Output difference image

Supports .png, .gif, .jpg, and .ps image formats.

Images should be the same size for meaningful comparison. Output shows pixel differences, not perceptual differences.

compare(1), diff(1)