Mosaic to Smooth Gradient Tool
Drag a box around a mosaic and it is replaced with a smooth patch of color that blends the block colors with the surrounding pixels. It is useful for tidying leftover pixelation in slides or stock images. It does not recover the hidden original: whatever the mosaic destroyed stays gone. Your image is never uploaded; everything happens in your browser. To add mosaic or blur instead, use the Image Blur & Mosaic tool.
🔒 Runs in your browser · Your data is never sent to a server
You can also drag and drop an image file here
Estimates the size and position of the mosaic blocks from color edges inside the selection. Turn it off and set the size yourself if detection fails.
Higher keeps more of the color variation from the mosaic. Lower fills smoothly from the surrounding colors only.
Adds grain that matches the noise level of the surrounding image. At 0% the patch looks painted and perfectly smooth.
Image being edited (drag around the mosaic)
Drag a box slightly larger than the mosaic (or swipe with your finger on a phone) to replace that area.
In Select area mode, swiping on the image selects an area and the page will not scroll. Switch to Scroll to move the page.
How to use
- Choose an image file (drag & drop also works).
- If needed, adjust "Auto-detect block size", "Mosaic color influence" and "Grain (noise)".
- Drag a box slightly larger than the mosaic. You can mark several areas in a row; press "Undo last" if you make a mistake.
- Choose a save format and download the edited image.
Notes
- This tool does not recover what a mosaic hid. It only builds a plausible smooth color transition from the mosaic colors and the surrounding pixels and swaps it in.
- It works best where color changes gently: sky, walls, skin, gradient backgrounds. Fine patterns, text, and faces cannot be reproduced and become soft blobs of color.
- Select a little more than the whole mosaic. If the box is too small, leftover blocks outside it are treated as surrounding color and a trace remains.
- Auto-detection works when block edges are crisp. If JPEG compression has smeared them, or the box contains a lot of non-mosaic area, set the block size manually.
- The larger the area, the flatter the replacement looks. Raising the grain helps it blend with the surrounding texture.
- Please do not use it to read personal information or content from other people’s images, or to strip censorship from images.
- Metadata such as EXIF (camera info, GPS location) is dropped because the image is re-encoded on export. For GIFs, only the first frame is used.
- All processing happens in your browser — the image you select is never sent to a server.
Glossary
Mosaic block
One of the small single-color squares that make up a mosaic. The longer its side (the block size), the coarser the mosaic.
Interpolation
Estimating the colors in between from known points by blending smoothly. Here, the colors just outside the selection act as the boundary and the inside is filled in.
Grain (noise)
The fine roughness in a photo. A purely interpolated patch looks unnaturally smooth, so grain at the surrounding level is added to blend it in.
FAQ
Can it recover the original picture under the mosaic?
No. A mosaic keeps only the average color of each block, so the fine detail is gone. This tool just builds a plausible smooth color transition from the block colors and the surrounding pixels; faces and text are not reproduced.
What kind of image gives the best result?
Places where color changes gently, such as sky, walls, skin, and gradient backgrounds. Fine patterns, text, or busy backgrounds turn into soft, flat patches of color.
What if the block size is not detected automatically?
Turn off "Auto-detect block size" and enter the side length of one mosaic block yourself. Detection is more likely to fail when JPEG compression has smeared the block edges or when the box contains a lot of non-mosaic area. Even without detection, the area is still filled from the surrounding colors.
The replaced area looks too flat and stands out. What can I do?
Raise "Grain (noise)" to add noise matching the surrounding image so it blends in. Also select a little more than the mosaic instead of fitting it exactly, which makes the seam less visible.
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