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Upload two images and drag the slider to compare them side by side. Great for showing edits, restorations, design revisions or progress photos.
This tool displays two images side by side, or overlaid with a slider, so you can directly compare differences between them — useful for checking before/after edits, comparing compression results, spotting differences between versions of a design, or reviewing changes between two photos.
The comparison happens entirely in your browser — both images are displayed locally and never uploaded to a server.
For the clearest comparison, use two images of the same dimensions and similar framing — comparing a cropped version against an uncropped original, for example, can make differences harder to interpret since the images won't align. When checking compression results specifically, comparing at 100% zoom (rather than a scaled-down preview) gives a more accurate sense of any quality difference, since some compression artefacts are only visible at full resolution.
A side-by-side view shows both images at once, which is useful when you want to take in the overall composition of each image and compare them as wholes — useful for design revisions where layout or colour balance has changed broadly. A slider overlay, where dragging reveals more of one image and less of the other, is better suited to spotting localised differences in the exact same frame — for example, checking whether a specific object was removed, whether a particular area looks blurry after compression, or whether a small edit (like a colour correction on one element) was applied correctly. If you're not sure which differences matter most, starting with the slider view and dragging slowly across the whole image tends to surface small differences that a side-by-side view can make easy to miss.
One of the most practical uses of an image comparer is deciding how aggressively to compress an image. Compression always involves a trade-off between file size and quality, but "how much quality loss is acceptable" is subjective and depends on the image and its intended use — a photo that will be displayed at thumbnail size can tolerate much more compression than one that will be viewed full-screen. By compressing an image at a few different quality levels with Image Compressor and comparing each result against the original here, you can find the point where file size drops significantly without a corresponding drop in visible quality — often there's a "sweet spot" where further compression saves relatively little additional size but starts to introduce visible artefacts.
When reviewing a design or document that's gone through revisions, it's easy to miss small changes — a shifted margin, a slightly different shade of colour, a typo correction — when looking at two versions separately, since memory of the first version fades by the time you're looking at the second. A direct side-by-side or overlay comparison removes this memory dependency entirely, since both versions are visible (or rapidly switchable) at the same time. This is particularly useful for reviewing changes made by someone else, where you need to confirm exactly what was changed without re-reviewing the entire document from scratch.
If you're comparing compression results and want to try a different quality level, our Image Compressor lets you re-compress and compare again. If you're comparing a cropped or resized version against the original, Image Cropper and Image Resizer can help you adjust further based on what the comparison reveals.
They don't have to be, but comparisons are clearest when both images have similar dimensions and framing, so differences are easy to spot rather than obscured by scale differences.
This tool is designed for comparing two images at a time. For comparing more images, you'd repeat the process with different pairs.
JPG, PNG and WebP images are all supported for comparison.
Yes — comparing an original against a compressed version side by side or with a slider is a quick way to assess whether the quality reduction is noticeable for your use case.
No. Both images are displayed and compared entirely within your browser.