How to sort and label large image libraries?

[grayestofghosts]

Hi, I've been hoarding images and other data for a while but this is the first time I've gotten around to really trying to organize them and am looking for some help. I've been working on a library/archive/time capsule project that includes a large amount of images and I feel like some of them need context to understand and want to preserve that information for possible future users. I have a Mac computer so I've started labeling things with tags but I understand that this feature doesn't transfer across file systems. While poking around I found that .jpegs have a comments field in their metadata but this isn't reliably preserved, even on the same Mac it seems -- if I put a comment on a .jpeg on a flash drive, disconnect the drive and reattach it, I can't see it anymore. It seems like the only reliable method of attaching data would be through the directory tree and file name, and maybe a text document in the folder explaining some things that need more explanation cross referencing by the file name? Are there any methods I'm missing that aren't too fragile/unreliable/non-transferrable? Thanks.