@derangedhermit:
I
posted a mini-tutorial (tutorialette?) on how to use Gimp for basic image rehab some time ago.
Personally, I use imagemagick and batch processing whenever there are many images and I can get away with it.
Regarding fleurons and such, I seldom come across any which it is worth transferring to the ebook. However, in those cases, I normally spend some time converting them as neatly as possible to svg. The only book I can remember I have done it in is
English as she is spoke
Otherwise, I use stock fleurons from a free fleuron font. However, I normally convert them to svg, rather than importing the font. It's more robust, scales better, and degrades better that way.