I use Supermemo every day for all of my learning (Languages, history, science,
etc.). Originally I used it only for languages, but as I saw how useful it could
be I could not resist and use it for many more aspects of my intellectual life.
I currently have nearly 29,000 flashcards that span many subjects.

I have no experience in other programs, but I have no desire at this point.
Supermemo is like a weird uncle; Supermemo does weird things, some things can be
explained, others cannot, but the pros outweigh the cons, I would never think
twice about using another program.

Images can be added easily, but I haven't experimented with video before...
animated GIFs load just as easily as images (Which I find myself using more
frequently).