Image Side-by-Side Comparer
Upload two images and compare them with a draggable vertical divider — perfect for before/after photo editing, design revision reviews, and image quality checks. Drag the slider to reveal any portion of either image, zoom in up to 4× to inspect fine details, and download a side-by-side PNG. All processing runs locally in your browser. No signup required.
Upload two images and compare them with a draggable vertical divider. Drag the slider to reveal more of either image — perfect for before/after comparisons, design reviews, and image quality checks. All processing runs locally in your browser.
Left Image (Before)
Right Image (After)
Why Use Our Image Side-by-Side Comparer?
Draggable Divider Comparison
Drag the vertical divider left and right to reveal any portion of either image. The divider is keyboard-accessible and touch-friendly — works on desktop, tablet, and mobile.
Zoom & Pan Controls
Zoom in up to 4× to inspect fine details in both images simultaneously. The zoom applies to both images at once, keeping the comparison aligned as you examine specific areas.
Secure & 100% Private
All comparison processing runs entirely in your browser. Your images never leave your device — no server upload, no cloud processing, no data retention of any kind.
100% Free — No Signup Required
Completely free with no account, no premium tier, no usage limits, and no watermarks on the downloaded comparison PNG. Compare images as many times as you need.
Common Use Cases for Image Side-by-Side Comparer
Photo Editing Before/After
Photographers and retouchers use the image side-by-side comparer to review edits against the original — drag the divider to see exactly what changed in each area of the photo.
Design Revision Review
Designers use the image comparer to present design revisions to clients — the draggable divider makes it easy to show exactly what changed between versions without switching tabs.
UI & Frontend Development
Frontend developers use the image side-by-side comparer to compare screenshots of UI changes — catching unintended layout shifts, color changes, or rendering differences between builds.
Product Image Quality Check
E-commerce teams use the image comparer to compare compressed product images against originals — verifying that compression artifacts are acceptable before publishing.
Image Processing Validation
Developers testing image processing pipelines use the comparer to validate filter outputs, compression results, and format conversion quality against source images.
Content & Marketing Review
Marketing teams use the image side-by-side comparer to review A/B test variants, banner revisions, and social media image updates before publishing.
Understanding Image Side-by-Side Comparison
What is Image Side-by-Side Comparison?
Image side-by-side comparison is a technique for visually evaluating differences between two images by displaying them in the same viewport with a movable divider. Unlike switching between two separate tabs or windows, the draggable divider approach lets you see both images simultaneously at the exact same position — making it easy to spot subtle differences in color, sharpness, layout, or content. Our image side-by-side comparer implements this using CSS clip-path and pointer events, running entirely in your browser with no server processing required.
How Our Image Side-by-Side Comparer Works
- Upload Two Images: Drop or select your left (before) and right (after) images. Any format is supported — PNG, JPG, WebP, GIF, BMP. Images are loaded directly into the browser and never sent to any server.
- Drag the Divider to Compare: The comparison viewer shows both images overlaid in the same viewport. Drag the vertical divider left and right to reveal more of either image. Use the zoom controls to inspect fine details. The divider is also keyboard-accessible — use arrow keys to move it precisely.
- Download or Share:Click “Download Side-by-Side PNG” to export both images placed next to each other as a single PNG file — useful for sharing comparisons in documents, presentations, or reports.
What the Comparison Viewer Shows
- Draggable Divider: A vertical line with a handle that you drag left and right to control how much of each image is visible. The divider position is shown as a percentage at the bottom.
- Image Labels:“Left” and “Right” labels are overlaid on each side so you always know which image you are looking at.
- Zoom Control: Zoom from 25% to 400% to inspect fine details. Both images zoom together, keeping the comparison aligned.
- Dimension Warning: If the two images have different dimensions, a warning is shown. Both images are scaled to fit the comparison viewport — the divider still works correctly.
Important Limitations
The comparison viewer scales both images to fit the viewport — if the images have very different aspect ratios, one may appear letterboxed. The downloaded side-by-side PNG places both images at their original pixel dimensions, which may result in a very wide file if both images are large. For pixel-accurate comparison of image processing results, use the Image PSNR Calculator tool which computes quantitative quality metrics.
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Frequently Asked Questions About Image Side-by-Side Comparer
The image side-by-side comparer lets you upload two images and compare them using a draggable vertical divider. Drag the slider left and right to reveal more of either image — perfect for before/after comparisons, design reviews, and image quality checks. All processing runs locally in your browser.
Click and drag the vertical divider handle left or right to control how much of each image is visible. You can also use the arrow keys on your keyboard to move the divider precisely. On touch devices, tap and drag the divider handle.
No. The comparer works with images of any size. If the images have different dimensions, a warning is shown and both images are scaled to fit the comparison viewport. The divider still works correctly regardless of dimension differences.
No. All comparison processing runs 100% locally in your browser. Your images are loaded directly into the browser using object URLs and never sent to any server. Nothing leaves your device.
It exports both images placed next to each other as a single PNG file at their original pixel dimensions. This is useful for sharing comparisons in documents, presentations, or reports. The output file is named "comparison.png".
The comparer accepts PNG, JPG, JPEG, WebP, GIF, and BMP files. Both images can be different formats — for example, you can compare a PNG original against a compressed JPG version.
Yes. Use the zoom controls above the comparison viewer to zoom from 25% to 400%. Both images zoom together, keeping the comparison aligned. Click "Reset" to return to 100% zoom.
Yes. The image side-by-side comparer is 100% free with no signup required, no premium tier, no usage limits, and no watermarks on the downloaded comparison PNG. Compare images as many times as you need, directly in your browser.