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Why is there no border around my collage even though I set spacing between the photos?

Because “Gap between images (px)” only separates the photos from each other; the outer frame comes from a different field, “Outer margin (px)”. Set the margin equal to the gap for an even frame on every side. The cells shrink a little, because the output width stays exactly what you entered.

Published · 3 min read

Gap and margin: two fields, two jobs

  • Gap: the strip between neighbouring photos, across and down. In a two column grid there is one gap per row.
  • Margin: the strip around the whole collage on all four sides, between the photos and the edge of the file.
  • Both use the same background color; you cannot color one differently from the other.

So with a 20 px gap and a 0 margin, the photos run right to the edges of the file, and the collage looks like tiles separated by lines with no frame at all. Some designs want exactly that, but it is not what you expect if you are after a framed, mounted look.

Worked example

4 photos in 2 columns, a 1080 width, a 20 gap, 0 margin and a 1:1 cell: each cell is 530 × 530, and the first photo starts right at the edge.

The same settings with a 20 margin: the first photo starts at pixel 20, each cell is 510 × 510, and the output is still 1080 × 1080. With a 40 margin the cells are 490 × 490 and the frame looks wider than the dividers.

How the tool sizes the cells

In the Image collage maker maker the width you type is fixed. The tool subtracts the margin twice, left and right, then the gaps between columns, and divides what is left by the number of columns. In the example: 1080 minus 40 of margin minus 20 of gap is 1020, split over two columns gives 510. So every extra pixel of margin comes out of the photos, not from outside the collage. If the remainder gets too small, you see “The width is too small for this gap and margin”.

I set a margin and still see no frame

  1. Check the background color. White is the default, and apps such as Instagram and WhatsApp usually show photos on white in light mode, so a white frame melts into the app and seems not to exist. Pick a slightly different light color, such as beige or pale grey, and the frame appears.
  2. Check “Transparent background (PNG and WebP only)”. With transparency the margin is see-through, so it takes whatever color sits behind the image on the platform.
  3. Check the numbers. Gap and margin accept 0 to 400 px, and a small value like 4 on a 4000 px wide collage is barely visible once a phone shrinks the image.

Proportions that look balanced

  • Margin equal to the gap: an even frame and a calm look, good for product grids.
  • Margin twice the gap: a wide frame around thin dividers, like a mounted print.
  • Gap and margin at zero: photos touching edge to edge, suited to continuous shots or a wide banner.
  • The same number looks smaller on a wider collage, so a 20 margin at 1080 wide is far more visible than at 4000.

Common questions

Can the margin be on one side only?

No, one margin value applies to all four sides.

Does the margin work in the featured layout?

Yes, gap and margin apply to both layouts, and the width stays what you entered.

Do I need another tool to add a colored frame?

No. The margin in the background color you choose is the frame. The tool does not add a separate border in a second color.