Merge Images - Combine Images Side by Side or Stacked

What Merge Images Does

This tool concatenates several images into one file along a single axis. Choose "Side by side" and it measures every image, adds up their widths, adds the spacing between neighbours, and makes a canvas that wide; the canvas height is the height of the tallest image in the set. Choose "Stacked" and the same arithmetic runs on the other axis: heights are summed, and the canvas width comes from the widest image. Each image is then drawn once at its native pixel size, in the order shown in the list, with no scaling of any kind. That last point matters more than it sounds. If your images are not all the same height in a side-by-side merge, the shorter ones cannot fill the canvas, so the leftover strip above or below them is painted with the background colour, and the Align setting decides whether a short image sits at the top, the middle, or the bottom of its slot. The same applies to narrower images in a stacked merge. Spacing works the same way — it is background colour, not empty pixels, so a gap of 20px between two photos is a 20px band of whatever colour you picked. Output is PNG or JPG. PNG can keep the background genuinely transparent, which is useful when your sources have transparency of their own; JPG cannot, because the format has no alpha channel, so a transparent choice falls back to white. This is a linear join only: no grids, no templates, no automatic layout.