Want to assemble images randomly into one? That’s easy in the command line if you have imagemagick installed:
Assuming you have all pictures in the current directory:
for i in *jpg ; do mv "$i" $RANDOM.jpg ; done
this renames all files ending in jpg into files that have a random number. Files might get overwritten should the random number come up again.
Assembling is as well:
montage *jpg -mode concatenate outputfilename.jpg
If you would run this again outputfilename.jpg would be a used as source image as well.