Save them!
Geh: once a part of the pekwm project.
Features:
- native GTK+ interface,
- control of several keys,
- thumbnails grid.
Issues:
There is no file open dialog in the program. There are also some bugs. For example, the rotate function breaks images.
PyBookReader: this is amazing application. A lucky choice of programming language and high developer's skill allows it to remain relevant for over 13 years after last release.
Features:
- extensive settings for easy reading,
- automatic scrolling,
- two-page mode.
- text from pdf files is rendering by system settings.
Issues: Various errors have accumulated by now.