Paint over it. Let the photo fill the hole.

Removing something from a photograph is a reconstruction problem. The pixels under the object were never recorded, so the program has to invent them from the pixels that surround the hole. Every tool does that in one of two ways: it either learns from millions of other photographs what usually goes in such a place, or it continues the pattern immediately around the mask. The first needs a server and a model. The second is what a browser can do in a second, and it is remarkable how often it is enough.

The fill on this page is a diffusion. Starting from the rim of the mask, colour and brightness are averaged inward until the hole is covered. That produces a smooth field that continues a gradient: a sky becomes lighter toward the horizon exactly as it did beside the hole, a wooden floor keeps its tone, a shaded wall keeps its falloff. On its own, though, a diffusion looks like a smudge, because it has no grain.

The second ingredient: borrowed detail

A photograph is not just colour, it is also texture — the fine, high-frequency variation of a real surface. The tool separates the two: it keeps the smooth field, then samples the detail from the nearest known pixels and adds it back inside the mask. That is why a plain wall keeps its plaster and a patch of grass keeps its blades instead of turning into a blurred stain.

This borrowing is also the source of the failures. If the nearest known pixels are a different material than the area being filled, the texture is wrong: a brick line can continue across a window, a shadow can stop abruptly. The practical response is to keep masks small and to paint the object plus its shadow, so the borrowed detail comes from the same material on both sides.

Painting better masks

Most disappointing results come from the mask, not the algorithm. Three habits fix almost all of them. First, paint ten to twenty pixels beyond the visible edge of the object; the soft boundary of a lens blur extends further than the eye expects. Second, include the shadow — a removal that leaves a shadow looks wrong even when the object is gone. Third, if the area is large, do it in two halves: the first pass gives the second one more known pixels to work from.

When a desktop editor is the honest answer

Content-aware fill in a professional editor does the same job with more compute, and a retoucher can clone texture precisely where a diffusion guesses. If the hole covers a face, a page of text, a product logo or a high-contrast pattern like a tiled roof, use those tools. This one is built for the everyday case: a cable across a product shot, a sign in the corner of a landscape, a stranger at the edge of a group photo, dust on a scan.

A workflow that keeps you out of trouble

• Work on a copy. The original is the only undo that always works.
• Fill the biggest object first, then the small ones that end up next to its edge.
• Check the result at 100%, not zoomed out — errors hide in thumbnails and shout at print size.
• Export PNG, and keep a note of which areas were rebuilt in case the picture is used at a larger size later.

One last thing worth knowing: the fill runs entirely in the tab, so the picture never leaves your machine and nothing is logged. That makes the tool usable for documents, ID photos and client material that a cloud service would not be allowed to see — a practical advantage that has nothing to do with the algorithm and everything to do with where it runs.

Dust, scratches and old scans

Family photographs and book scans are the quiet success story of this kind of fill. A dust speck, a scratch or a crease is small, sits on a surface with an even texture, and therefore heals almost invisibly. Work at a large brush size for the whole scratch, not point by point: the mask should cover the damage plus a margin, and the texture matching will borrow the paper grain from both sides.

The limit arrives with anything printed underneath. A scratch across a face, a caption, or a printed halftone pattern leaves a smooth patch the eye can find. In those cases the honest answer is a clone tool in a proper editor, used sparingly, with the original kept untouched next to the result.