Although I don't yet have astronomy pics to deal with, I do have a lot of other data that I must manage and seeing as how I have 9 computers on my network here I have found a cost effective solution to my storage issues to be by using a homemade network attached storage device.
It may not be feasible for everyone depending on your computer situation but if you are running any kind of local area network, you can easily build such storage using an old computer you may have lying around and then add some large hard drives. One of the great things about these systems is that they are bios independent so old hardware restrictions on hard drive sizes aren't an issue. The files are readily available and they are easily shared between all computers on the network. Backups are also easy to implement with this type of system so those rare photos won't get lost in the event of a catastrophic system failure.
Basically all you need to invest in is the
software package, which is quite inexpensive, and then the hard drives and you are in business. I'm using an old Pentuim 233 Mhz system running headless with several 320 Gb hard drives here. You can stick the box in a corner with just a power and network cable connected and it also keeps the old hardware out of the landfills.
As I said, it may not be the solution for everyone, but it works a treat for my situation.