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About this tool
Compare two images interactively with a draggable before/after slider. Perfect for showcasing edits, restorations, and transformations.
The Before/After Slider overlays two images in one frame and reveals them with a wipe divider you drag left or right, starting centred at 50 percent. The container locks itself to the before image's natural aspect ratio so neither picture is stretched, and the divider can be moved by mouse, by touch, or with the arrow keys on the range control beneath it. It is for showing an edit, a repair or a renovation where a side-by-side pair loses the point and the change needs to land in a single frame.
Open Before/After Slider on AltFTool — it loads instantly in your browser.
Load a file into the Upload Before Image panel and another into Upload After Image — both take PNG, JPG, WEBP, BMP or GIF, and until both are in, the card reads Upload both before and after images to start comparing
Drag the circular handle on the divider, or the range control under the frame, to wipe between the two pictures; the corners stay tagged Before and After, and Swap Images trades the two sides while Reset clears them and returns the divider to 50%
Check the Output Summary panel, which prints each filename with its pixel dimensions and the current Slider position as a percentage
The frame adopts the before image's own width-to-height ratio, so nothing is squashed to fit a fixed box.
The same position is driven by pointer drag, touch drag and a labelled 0-100 range input, so it works without a mouse.
One button exchanges the before and after images and recentres the divider at 50 percent.
Drag it with the mouse, swipe with a finger on touch screens, or focus the range slider below the image and use the arrow keys. Its position runs from 0 to 100 percent of the frame width and starts at 50.
They should share the same aspect ratio and framing for the wipe to line up. The frame sizes itself from the before image's natural dimensions, and the output summary lists both images' pixel width and height so a mismatch is easy to spot before you present it.
Anything the browser can display — JPEG, PNG, WebP, GIF and AVIF among them. Each file is read into an object URL locally, so large images load without any upload wait.
This tool is for viewing and presenting live rather than exporting; there is no download step. If you need a single saved image with both halves labelled, use a comparator that renders the pair to a PNG instead.