How to Compare Two Pictures With a Before and After Slider

A side-by-side pair of pictures is fine, but a slider lets people judge the exact change by dragging across the same spot. It is the clearest way to show an edit.

Quick answer

Choose a "before" picture and an "after" picture, then move the slider to reveal one over the other. The pictures stay on your device.

What it is good for

• Photo retouching and colour grading.
• Home renovation and interior design.
• Design changes such as website redesigns and logo updates.
• Image compression to see whether quality was lost.
• Education to show growth or change over time.

Steps

1. Open the tool and add the first picture.
2. Add the second picture.
3. Drag the slider left and right to compare.

For the best comparison

• Use pictures of the same size and framing. A tripod or a grid helps when you take photos over time.
• Keep the same lighting and angle.
• Put the original on the left and the changed version on the right.
• Zoom in on the area that matters.

Sharing the result

The slider works on screen; to share a still, take a screenshot with the slider at the centre, or place the images side by side with the Merge Images tool.

Tip for checking compression

Compare an original photo with the version you made at 100 KB: if you cannot see the difference at the slider, the smaller file is good enough.