Compare Two Images Before and After

A wipe comparison beats flipping between tabs because your eye holds a fixed anchor while content changes across the line. Compression artefacts announce themselves at the boundary: ringing around text, blocking in flat skies, smeared fine texture. Two seconds of sweeping settles arguments that paragraphs of quality-setting talk cannot.

The classic inspection targets: hard edges and lettering (where JPEG ringing concentrates), smooth gradients (where banding and blocking appear first), fine repetitive texture like fabric or foliage (the first thing encoders smooth away), and faces (where retouching or model-based processing shows as plastic skin). Park the divider mid-feature rather than sweeping fast — the discontinuity along the line is what your visual system is built to catch.

The exported side-by-side is deliberately a plain PNG: it drops into a pull request, a client email, a bug ticket or a slide without any viewer requirement. Both halves are scaled to matching height with a thin separator, and PNG is used so the export itself adds no compression artefacts to a comparison about compression artefacts.

Nothing requires the two images to be versions of the same shot — the slider works equally well for two crops, two edits, or two products photographed identically. It simply works best when geometry aligns, since the wipe then reads as one image transforming rather than two images swapping.