However, none that I have found so far allows variable-size tiles. That is, let's say that one tile is 2:2, another is 3:5, another is 2:10, etc.
Is there a mosaic software that allows variable-size-tiles?
The software should accept a directory of images to be used as the tiles in the mosaic and an input image and act on these inputs.
This would ideally be free-of-charge and run on Mac, but I am open to answers for any OS and proprietary software.