A lightweight python utility to convert Blender PNG output into a single large spritesheet.
Suppose you exported a Blender animation as a series of PNGs to folder ~/output. Assuming that imgtosheet is in your path, use the following commands to create a spritesheet:
$ cd ~
$ imgtosheet ./output/ ./output_spritesheet.png
This will produce a spritesheet from the PNGs at location ~/output_spritesheet.png.