Prepare a meaningful comparison
- Choose two images showing the same or closely aligned scene.
- Move the reveal slider across important detail and edge areas.
- For pixel-difference statistics and a heatmap, use images with identical pixel dimensions.
Before and After Image Comparison & Difference
Compare two local images with a reveal slider, exact source facts, quantitative pixel-difference statistics, and a downloadable difference heatmap when dimensions match.
A reveal slider helps visual inspection, while an aligned pixel-difference pass can locate and quantify edits, compression changes, restoration work, or retouching without uploading either image.
How OpenFileTools processes it
Local processing, explicit choices.
Both files are decoded locally for the reveal view. When dimensions match, a bounded common-size sample is compared channel by channel to calculate changed-pixel ratio, MAE, RMSE, and a downloadable exaggerated difference heatmap.
Questions, answered.
Does comparison alter either image?
No. The originals stay untouched; the optional heatmap is a separate generated visualization.
Can I compare compressed and original versions?
Yes. Identical dimensions are ideal because they also enable pixel-difference analysis.
Related guide
Read the related guide