Image Compare
Upload two images and compare them side by side, with a slider, overlaid, or by seeing exactly which pixels change between one and the other.
The 4 comparison modes
Switch modes at any time once both images are loaded — no need to re-upload them.
| Mode | What it's for |
|---|---|
| Side by side | See both full images next to each other |
| Slider | Drag a line to progressively reveal A or B at the same spot |
| Overlay | Adjust B's opacity over A to spot shifts or subtle changes |
| Difference | Highlight in magenta exactly which pixels change between the two images |
What the difference percentage means
It compares each pixel's color channel by channel (red, green, blue and alpha) with a small tolerance margin, so normal compression noise isn't flagged as "different." It's not a measure of how different the image looks to a human: two images with 5% of pixels different could look very different if that 5% is, say, added text, or nearly identical if it's just scattered noise.
When the images have different sizes
Difference mode needs both images to be the same size to compare pixel by pixel. If they don't match, you can choose to scale B to A's size — but the scaling itself can introduce differences that don't exist in the original files, so the result is an approximation, not an exact comparison.
Privacy
Both images are compared entirely in your browser with <canvas>. Neither one is uploaded to Numelto.