Just a short post that should prove useful if you’ve had trouble finding good pictures for prepositions (on, over, between) or directions (up, down, top, bottom).
I found a lovely image of 29 prepositions in English on a language learning site for French students of English, Angloxchange. It has a bunch of English labels on it, but I cut the image up into little chunks, so you should be able to drag and drop your favorites into Anki.
New: A reader just suggested a Slovak website with 12 preposition images in the forms of cute sheep. If you prefer sheep to red balls, check them out here.