This old question asked how to combine 2 images into a single image side by side.
I want to do something different - combine 4 images into a grid.
So I have 4 png files, all the same size
+----------+ +----------+ +----------+ +----------+
| | | | | | | |
| | | | | | | |
| PNG 1 | | PNG 2 | | PNG 3 | | PNG 4 |
| | | | | | | |
| | | | | | | |
+----------+ +----------+ +----------+ +----------+
What I want to end up with is a single png file like this:
+----------+----------+
| | |
| | |
| PNG 1 | PNG 2 |
| | |
| | |
+----------+----------+
| | |
| | |
| PNG 4 | PNG 3 |
| | |
| | |
+----------+----------+
I actually have 34 sets of 4 files that I want to combine like this.
How can most easily I do this via the command line in macOS?
FWIW I currently have installed the latest versions of
Affinity Photo
Affinity Designer
Inkscape (with the extension for running python scripts inside Inkscape)
So anything that fits into one of these applications would be preferred.