I'm having an issue with thumbnailing: pcmanfm uses 100% CPU and fills the RAM very fast. This would presumably stop at some point but I don't have enough RAM, "only" 2GB.
The issue happens when thumbnailing the attached image, which has the following characteristics:
1.1MB, PNG image data, 24832 x 10496, 8-bit/color RGB, non-interlaced
Less than 1.5MB, but opening it with a "naive" viewer uses more than 2GB of RAM.
I set the maximum file size for thumbnailing to 1.5MB in pcmanfm, which is how it happened.
Maybe it would be possible to cancel thumbnailing when the free memory reaches 80% of the amount of available RAM? As for measuring "free" (unreclaimable) memory, this can help: http://calimeroteknik.free.fr/blag/?article20/really-used-memory-on-gnu-linux