Grid Rearrangement

[gasMask]

If the process is repeated, then Roller can do this from a preset file. The design would be to set up two Table models, one for each grid. As such, Roller could render two layer groups corresponding with the grids. The first grid could place the images using a Next image source. With the second grid, the cells would be assigned images on a Per Cell basis using the Numeric Order image source. The trick is that the images would have to be already opened in GIMP in the order of the first grid. If the grids have different scales, then layer margins can be used. The output of the eventual saved file can be switched with layer group visibility.

I published Roller 3.20 yesterday. Unfortunately the file is too large to add as an attachment, so I provide a link:
on gimplearn.net