I have an external hard drive, not always connected to my laptop. I don't use it for Time Machine, as it's not big enough, and most of my important documents are on DropBox... Plus I only connect it a few minutes per week when I need to copy something.
For iPhoto, I found the Library file and I manually copy it to my external drive once in a while. The problem I have with that, is the file is growing big (22GB last I checked), and I feel like it's a waste to wait so long for copying the entire file, while I'm really only adding the last GB for example.
Is there a way to just add the increment?
Keep in mind again I only connect my external drive when needed.