Image Comparison
Compare two images side by side or with a slider.
Runs in your browser, nothing is uploadedFree, no signupNo watermark
Three steps
How to use the image comparison
- 01
Add two images
Drop in a before and an after, or any two versions you want to check against each other.
- 02
Choose a comparison mode
Side by side for overall differences, or the slider for spotting exactly what changed and where.
- 03
Judge at full size
Zoom into the areas where a difference would show first, like edges and flat gradients.
Why this one
What makes it different
A slider, not just two panels
Small differences are invisible between two separated images and obvious when one wipes over the other in the same position.
Both modes, because both are needed
Side by side answers "are these different"; the slider answers "different where".
Settles compression arguments
The honest way to choose a quality setting is to look at the two files in the same place at full size, which is exactly what this does.
How this tool handles your files
- Where it runs
- Your browser, not a server
- Uploads
- None, ever
- Account
- Not required
- Watermark
- Never added
The short version
About image comparison
Almost every decision about image quality comes down to whether anyone can actually see the difference, and that question is unanswerable when the two versions are in separate tabs. Putting them in the same place, with a slider wiping between them, turns an argument about numbers into something you can settle by looking.
Questions
Image Comparison FAQ
What is this useful for?
Deciding whether a compression setting is acceptable, checking an edit against the original, showing a client a before and after, or confirming that a conversion did not change anything it should not have.
Do the images need to be the same size?
For the slider, yes, or the comparison is meaningless because the two are not aligned. Side by side works with any pair.
Where should I look for compression damage?
Smooth gradients like skies, flat areas of single colour, and the edges of text or graphics. Detailed textures hide artefacts, which is why they are the wrong place to check.
Can it tell me the numerical difference?
No, it is a visual comparison. For most decisions that is the correct measure anyway, since the question is whether a person can see the difference rather than whether one exists.
Free, and staying free
The tools are free because the icons are the business.
Thridy is a library of thousands of 3D icons in one consistent style, free for commercial use with no attribution and no account. The tools exist so you never have to upload an image to somebody else's server to resize it.
Keep going
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