Image Diff -
Compare Two Images & Pictures Online
Compare two images online and spot even the smallest differences between photos, screenshots, and design mockups. Six view modes — side by side, fade, slider, flicker, pixel diff, and details — cover everything from a quick before-and-after to pixel-level visual testing, with no upload and no sign-up.
Your pictures stay completely private: the comparison runs in your browser with nothing sent to a server. That makes it safe for unreleased designs, private photos, medical imagery, and anything you'd rather keep off someone else's servers. No watermarks, no analytics, and nothing kept once you close the tab.
Six Ways To Compare Images And Photos
Pick the view that fits what you're trying to see, and switch between them freely without re-uploading — the same two images flow through every mode.
Side by Side. Both pictures in two panels next to each other, the quickest way to scan for layout, composition, or framing changes.
Fade. Stacks both images and blends between them with an opacity slider, so one picture dissolves into the other — ideal for subtle changes in the same scene.
Slider. Drag a vertical divider to reveal one picture beneath the other — the classic before-and-after swipe for photographers and designers.
Flicker. Auto-toggles between the two images in the same spot so any change appears to jump out; tap space to pause and step through manually. The astronomer's trick for spotting what moved.
Pixel Diff. Highlights every differing pixel. Heatmap lights changes in bright magenta while dimming the rest; Difference shows only the colour delta on black — with a sensitivity slider to tune how much counts as a change.
Details. A side-by-side table of every image's metadata, with the differences between the two called out — resolution, format, colour space, DPI, and more.
Pixel-Level Difference Detection
When you need to know exactly which pixels changed, the Diff mode does the work the eye can't. It compares the two images pixel by pixel using a perceptual colour-difference measure rather than a raw RGB subtraction, so it ignores imperceptible noise and flags the changes a person would actually notice. Heatmap view lights every change in bright magenta over a dimmed original; Difference view blacks out everything identical and shows only the colour delta.
A sensitivity slider sets the threshold — slide toward strict to surface only the boldest changes, or toward sensitive to catch faint compression artefacts, hidden watermarks, and sub-pixel shifts. It's the fast way to diff two screenshots for a visual-regression or cross-browser check, and the result exports as a PNG, so the difference leaves with you as a file rather than living on a server.
Compare Image Details And Quality
Two images can look identical and still differ in ways the pixels don't show. The Details view lays both files' metadata side by side and highlights what changed between them: dimensions and aspect ratio, file size with the exact byte and percent delta, format, colour space, bit depth, alpha channel, chroma subsampling, compression, interlacing, DPI, and EXIF orientation.
That makes it a quick way to compare image quality and file size — checking whether a JPEG-to-WebP conversion held up, why one export is heavier than another, or whether a re-save quietly stripped transparency or changed resolution. It answers the non-visual half of an image comparison that a pixel diff alone can't.
Supported Image Formats
PNG, JPEG, WebP, GIF, SVG, and HEIC all work out of the box, and you can even drop in a PDF page. Mix formats freely — a JPEG on the left and a WebP on the right compare just fine.
- PNG — Lossless with alpha transparency
- JPEG — Photos and high-colour images
- WebP — Modern web format, smaller than JPEG
- GIF — Simple graphics and short animations
- SVG — Vector graphics, rasterized for pixel diff
- HEIC — Apple device photos from iOS and macOS
How To Compare Two Pictures Online
Four steps — no sign-up, no installation, nothing uploaded.
- 01Add The First Image. Drag a picture onto the left panel, paste from the clipboard, or click to browse. It loads straight into the browser — nothing is sent anywhere.
- 02Add The Second Image. Drop the second picture on the right. The two line up automatically, aligned at the top-left so any size difference is visible.
- 03Choose A Mode. Pick side by side, fade, slider, flicker, pixel diff, or details, and switch between them freely without re-uploading.
- 04Zoom And Inspect. Zoom and pan into any area — linked across both panes or independent. Start with pixel diff to find changes, then flip to slider for a clean before-and-after.
Why Use This Image Compare Tool
Free, private, and watermark-free — built for quick photo comparisons and detailed pixel-level work alike. Eight things make it stand out:
- 01Six View Modes. Side by side, fade, slider, flicker, pixel diff, and details — every way you'd want to compare two images, switchable without re-uploading.
- 02Perceptual Pixel Diff. Differences are detected with a perceptual colour measure, not a raw subtraction, so it flags changes a person would notice and ignores imperceptible noise.
- 03Tunable Sensitivity. A slider sets how much difference counts, from only-bold-changes to faint compression artefacts and hidden watermarks.
- 04Full Image Details. Resolution, DPI, colour depth, format, colour space, subsampling, interlace, alpha, and EXIF orientation — with the delta between the two images called out.
- 05100% Private. Nothing is uploaded to a server. Safe for unreleased mockups, product photos under embargo, and medical scans — the images never leave the tab.
- 06No Watermarks. Nothing is stamped on your exports. The diff image comes out exactly as rendered, ready to drop into a bug report or review.
- 07Works On Mobile. Pinch to zoom and swipe to pan — every mode works on phones and tablets, not just desktop.
- 08Wide Format Support. PNG, JPEG, WebP, GIF, SVG, HEIC, and even PDF pages, mixed freely between the two sides.
Frequently Asked Questions
How do I find differences between two images?
Upload both pictures and open Pixel Diff. Heatmap lights every changed pixel in magenta, and Difference shows only the colour delta on black. Slider, fade, and flicker are better when you want to see both versions in context rather than just the changes.
Can I compare two photos side by side?
Yes. Side by Side mode places both photos in adjacent panels — the fastest way to do a quick before-and-after — and zoom and pan can be linked so both move together.
Can I compare two images for similarity?
Yes, visually. The tool overlays and diffs the images so matching areas read as identical and differences stand out — fade, slider, and flicker show how alike two pictures are, and pixel diff isolates exactly where they part. It's a visual comparison, not a numeric similarity score or facial-recognition match.
What is Flicker mode?
Flicker auto-toggles between the two images in the same spot, so anything that changed appears to jump while everything else stays still — the same trick astronomers use to spot moving objects. Press space to pause and step through the two frames manually.
How does the sensitivity slider work?
Pixel Diff compares images using a perceptual colour-difference threshold. The slider moves that threshold: toward strict to surface only obvious changes, or toward sensitive to catch faint artefacts, watermarks, and sub-pixel shifts that the eye would miss.
Can I compare image quality, size, or format?
Yes. The Details view puts both files' metadata side by side and highlights the differences — dimensions, file size with the exact delta, format, colour space, bit depth, compression, and DPI — so you can compare image quality and weight, not just pixels.
Can I compare pictures of different sizes?
Yes. The images are aligned at the top-left corner, and any area that doesn't overlap is treated as a difference, so a crop or a resize shows up clearly.
What formats are supported?
PNG, JPEG, WebP, GIF, SVG, and HEIC, plus PDF pages. Mix formats freely — SVG is rasterized at load time so it can be compared pixel for pixel.
Are my images private?
Yes. Everything runs in your browser — your images are never uploaded, stored, or sent to a server. That makes it safe for unreleased designs, embargoed product shots, private photos, and medical imagery.
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