This is a perl script I wrote to automate mucking about with multi-image 01-12.bmp's, since I tend to prefer my own wallpapers but still want waves and such. It's a commandline utility that automagically extracts jpegs and records their padded lengths, then adds the correct padding when rebuilding. I'm aware of other utilities out there but the one I have tried didn't work, and is a gui app which I tend to loathe.
Usage is as such: extracting
0112arc.pl -e 01-12.bmp
0112arc.pl -e 01-12.bmp imagedir
Now the images can be replaced with anything of the same size or smaller.
The directory can be left off and it will assume that it's BMPFILE-out. You will need an existing multi-image 01-12.bmp to extract. I have included a sample with 30 images, each allowed 32725 bytes.
GUI fooie! Having to use that horrid directory selection dialog is painful (looking at you ctftool :P). I have cygwin installed so it's usually a matter of
01<tab> /ps<tab>p3<tab>vs<tab>mo<tab>01<tab><enter>
>.>
For repeated use:
!01<enter>
:P