Before and after, with a slider you can present

Presenting a change rather than measuring it

A slider is the most persuasive way to show an edit: the eye tracks the divider and sees the change happen. The divider can be dragged, clicked into place, or moved with the arrow keys once focused (Shift for bigger steps). Labels can be renamed or hidden, the divider made thicker for a projector, and the whole workspace sent full screen.

Fade does the same job differently. At 50% opacity, anything that moved shows as a double edge, which is why retouchers use it to check that a healing brush did not shift a jawline.

Taking it with you

Export a static split at any divider position, or a side-by-side, at the width you choose. Where the browser can record a canvas, a four-second reveal animation is recorded in the page as WebM. There are no hosted share links, because that would require uploading the pictures — the file is yours to post wherever you like.

When the two photos are not quite aligned

Before-and-after pairs taken on a phone rarely line up: the second shot is a little closer or a little to the left. Auto-alignment estimates the scale and shift and corrects for it, and the Nudge controls in Fade move B by single pixels until edges sit on top of each other.