ComparePicture

Compare image quality, one measurement at a time

Which export is sharper? Which one clipped the sky? Which was compressed harder? Each number below answers one of those, measured on both pictures in the same frame.

Private · Browser-based · No uploads

Two pictures in, every difference out.

  1. 1. Drop, paste or choose the earlier picture as A.
  2. 2. Add the later one as B — or drop both at once.
  3. 3. The comparison starts by itself; switch views any time.

PNG, JPEG, WebP, GIF (first frame), AVIF, BMP and HEIC where this browser can decode it. Different sizes are fine — they are aligned for you.

Both files are read by this page on your device. There is no upload step, because there is no server to upload to.

Or try an example pair

AVersion AChoose image Adrag & drop, or paste with Ctrl/⌘ VPress Enter to choose image A, or drop a file here.
BVersion BChoose image Bdrag & drop, or paste with Ctrl/⌘ VPress Enter to choose image B, or drop a file here.

Why there is no overall winner

A denoised picture measures smoother and less sharp; a sharpened one measures crisper and noisier. Neither is “better” without knowing what it is for, so the Quality view reports each measure separately and writes sentences like “Image B has higher measured sharpness, while Image A has fewer clipped highlights.”

Measurements are taken after both pictures are placed in the same frame, so a larger file is not credited with detail merely for having more pixels. The file-level numbers — dimensions, file size, bits per pixel, the JPEG quality the quantisation tables suggest — are reported separately.

The sharpness map

Turn on the sharpness overlay to see, cell by cell, where each picture holds fine detail. “Inspect the sharpest difference” jumps to the cell where the two disagree most, at a zoom where you can judge it yourself.

Colour, side by side

Overlaid luminance and RGB histograms, the dominant colours of each picture with their share, the average colour, and a summary of the shift in plain words — warmer, cooler, lighter, more saturated — with the mean ΔE between aligned pixels.

Questions people ask

›Which one is sharper?

Compare the Sharpness and Edge strength rows. Both are higher for crisper detail. Check the Noise row too: noise raises both numbers without adding real detail.

›How is JPEG quality estimated?

From the file's own luminance quantisation table, matched against the standard libjpeg table at every quality from 1 to 100. Encoders that use custom tables will produce an approximate figure.