How the grid is laid out
Every photo gets a square cell. The canvas size comes from three settings: width = columns x cell + (columns + 1) x gap and height = rows x cell + (rows + 1) x gap, where rows = ceil(images / columns). The gap is also used as the outer margin, so a 10 px gap leaves a 10 px frame around the whole collage. Photos fill the cells left to right, then top to bottom, in the order shown in the file list.
Worked example
Six photos, 3 columns, a 400 px cell and a 10 px gap. That gives 2 rows, a width of 3 x 400 + 4 x 10 = 1240 and a height of 2 x 400 + 3 x 10 = 830. For a square Instagram-style 2 by 2 post, set 2 columns, a 540 px cell and gap 0 to get exactly 1080 by 1080 with four photos.
Cover-cropping, not stretching
Each source image is fitted to its square cell the way CSS object-fit: cover works. The tool compares the image's aspect ratio to the cell. A wide photo loses equal slices from left and right; a tall photo loses equal slices from top and bottom. The picture is never distorted, but the cropped edges are gone, so a portrait photo in a square cell loses a good part of its height. Small source images are enlarged to the cell size and will look soft.
| Setting | Range |
|---|---|
| Columns | 1 to 5 |
| Cell size | 50 to 1000 px |
| Gap / border | 0 to 100 px |
| Background colour | Any colour; fills gaps and unused cells |
| Output | JPG (default), PNG or WebP |
Limits and common mistakes
- If the last row is not full, the empty cells show the background colour and the photos stay left-aligned. Choose a column count that divides your photo count, such as 6 images in 3 or 2 columns, for a tidy rectangle.
- Drag a row by its ⠿ handle to change which cell a photo takes, or use the ↑ and ↓ arrows, which are the way to reorder on a touchscreen. Photos you add later always join the end of the list.
- Phones limit how large a canvas can be, so the collage is capped at 4096 px on its longest side and about 16 megapixels. If your settings would exceed that (the biggest, 5 columns of 1000 px cells with 100 px gaps, would be 5600 px wide), the cells and gaps are scaled down proportionally and a note above the preview shows the final size.
- A before-and-after pair in 2 columns will crop each image to a square, so frame the important part in the middle first with Crop Image.
- JPG and WebP are written at 92 percent quality. Reduce the file for sharing with the image compressor.