Clean up over-compressed images online

What happens when you compress an image too much?

Every time a JPEG is saved, the encoder permanently discards image data to shrink the file. At moderate compression the loss is invisible, but push past a certain threshold and the damage surfaces as compression artifacts: chunky 8×8 pixel blocks across flat areas, halos and fringing around sharp edges, smeared gradients, and an overall loss of clarity. Alongside blocking, over-compression also flattens tonal transitions: skies and smooth backgrounds that looked clean start showing visible stripes, because the encoder rounds similar tonal values into a single step and the gradient falls apart.

Why does re-saving a JPEG make it look worse each time?

Each encode is destructive and cumulative. The second time you save a JPEG, the encoder starts from a file that has already had its detail stripped once, so the new encode removes yet another layer of information. Re-encoding an already-compressed image compounds every artifact: blocks get blockier, banding gets more pronounced, and fine texture disappears entirely. A photo saved three times at the same quality setting will look measurably worse than one saved once. There's no reversing it. Discarded data is gone permanently.

How to recover quality from a compressed image

1. Go back to the source if you still have it. If the original RAW or high-quality TIFF is available, re-export from there at the highest quality setting and avoid any intermediate JPEG saves. Lossless formats preserve everything the encoder would otherwise discard.
2. Reduce artifacts in Photoshop. The Reduce Noise filter (Smart mode) targets JPEG blocks specifically. For banding and gradient smearing, a Surface Blur on the affected area followed by a thin luminance noise layer (0.5–2%) smooths the tonal steps and restores a natural-looking texture. Work on masked layers to protect areas that don't need it.
3. Clean up your compressed image online with our free tool above. Upload the file, choose how aggressively to correct it, and download a restored version. Handles blocking, banding, and gradient smearing across JPEG, PNG, TIFF, and more, with no account or software, right in the browser.

Want to learn more?

We wrote a whole article on the topic in our blog with a more detailed view on the problem and solutions: De-banding and fixing compression artifacts