Is it possible to change the location where proxy images are stored from internal_data/image_cache to something else? If so, any reason not to use a ramdisk?
They're generally just part of the internal_data structure, so you'd have to move all of it (unless you did something with symlinks/mount points). The images are mostly assumed to be permanent, though it should handle the files being removed, but it's not really designed with ephemeral storage in mind.
It's not really something I could comment on. I was mentioning it as an idea, but it's not something I've ever seen used in production (and by using temporary storage, it is leading to a potential case that the system isn't designed for, though it should survive it).