SD cards are a simple serial interface that is well-documented at the block-device layer; the filesystem will likely be some variant of FAT, and I doubt the JPEG standard will be entirely forgotten, so while hardware like SD card readers may not be produced commercially anymore by then, anyone with the right knowledge can still make one.

This is, of course, supposing that the rather scary situation of heavily-locked-down devices and completely-restricted access to knowledge has not occurred...