Find image differences
This image difference checker marks changed pixels in red so visible edits are easy to locate.
Browser-local pixel comparison
Image Diff Checker, Pixel difference results.
Use this image diff checker to find image differences, highlight changed pixels, tune the threshold, and read mean RGB delta, RMSE, and PSNR.
Pixel diff lab
Image Diff Checker
Load a real example or compare your own PNG, JPG, JPEG, or WebP file. This pixel difference checker updates scores after the local diff runs.
Images stay in this browser sessionPNG, JPG, JPEG, WebPPixel metrics update after Highlight Diff
Pixel match
Run local diffNeeds local diffChanged pixels
Run local diffNeeds local diffRMSE
Run local diffNeeds local diffHighlight Diff
Run a browser-local pixel difference checker to create a highlighted difference preview.
Lower values catch subtle changes; higher values ignore compression noise, tiny lighting shifts, and anti-aliasing. A pixel counts as changed when its maximum RGBA channel delta is above this value.
Image difference scores are pending
Analyze image differences
Run the browser-local image diff checker to fill the result chips and side metric cards.Visual changes
Run local diffNeeds local diffMean RGB delta
Run local diffNeeds local diffPSNR
Run local diffNeeds local diff1
Add images
Replace either side, then run the local diff for measured results.
Choose or drop a PNG, JPG, JPEG, or WebP file for Baseline image.
A
Baseline / before
Choose or drop a PNG, JPG, JPEG, or WebP file for Changed image.
B
Changed / after
2
Inspect diff modes
Highlight Diff is the primary image difference view; slider, side-by-side, and overlay help verify context.
3
Image difference results
Use Run pixel diff near the viewer for local image difference scores. It opens Highlight Diff and calculates in this browser.
Tune the pixel threshold
Use 8 for exact UI checks, 18 for photo detail, 32 for balance, and 64 for larger visual differences.
Read pixel difference metrics
Use changed pixel %, mean RGB delta, RMSE, and PSNR to explain how different the image pair is.
Diff metrics
Image difference checker metrics
The image diff checker separates visual review from computed pixel results. File details appear after loading; metrics update after the local diff runs.
Changed pixels
Counts pixels where this pixel difference checker finds a channel delta greater than the current threshold.
Difference percentage
Shows changed pixels as a share of all comparable pixels in the normalized image difference canvas.
RMSE and PSNR
Summarize RGB error. Lower RMSE and higher PSNR mean the images are visually closer.
Method
How the pixel difference checker works
Both images are decoded locally, drawn to a shared normalized canvas, then compared channel by channel. The threshold controls which pixels count as image differences.
Thresholded pixel difference
A pixel counts as an image difference when the largest red, green, blue, or alpha channel delta is greater than the selected threshold.
Comparable canvas
Images with different dimensions are centered on one canvas. Large files may be scaled to keep the browser responsive, and the result panel reports the scale.
Readable error metrics
Mean RGB delta, RMSE, and PSNR give a more technical view of the same local image differences shown by the highlight preview.
Use cases
Where a visual difference checker helps
Use the same browser-local image diff checker for practical review tasks where visible image differences need to be found quickly.
Screenshot difference checks
Use the visual difference checker to spot UI screenshot changes while allowing threshold tolerance for rendering differences.
Photo and product retouch review
Confirm where color, cleanup, shadows, or retouching changed between two exports with highlighted image differences.
Compression and export review
Compare JPEG, PNG, or WebP exports to see visible pixel differences after optimization.
AI-generated variant comparison
Compare two AI-generated image variants visually with local pixel measurements.
Portrait and face photo review
Compare portrait or face photos visually for retouching, expression, crop, or lighting changes.
FAQ
Image diff checker questions
Answers match the visible image difference checker: local image previews, thresholded pixels, and no server upload flow.
What threshold should I use?
Start with 18. Use 8 for strict UI screenshots, 18 for photo detail, 32 for a balanced review, and 64 when you only want large visible changes.
How do I know my images loaded?
If your images appear in the upload slots, they have usually loaded successfully. Very large image files can take longer to load and may slow down comparison.
Can I compare AI-generated images?
Yes. You can compare AI-generated variants as two selected images; the results are local pixel measurements.
Can I use it for face comparison?
You can compare portrait or face photos visually. The tool does not verify identity or perform biometric recognition.