Hi Anne and Polly,
Yes, morbror is uncle (maternal uncle),and moster is aunt (maternal aunt).
I was lucky enough to learn these words as a tiny child, so at least this part of the Swedish language is second nature to me. They are probably among the first Swedish words I ever learned.
Polly, you will often see these in combinations on the Swedish boards and lists, such as mmffm = mormors farfars mor = mother's mother's father's father's mother. :-) (Yes, you should get back that far, and even farther than that. Swedish genealogical records are superb.) Swedes are very exact in listing relationships, and this is much better than expressing the same relationships in English. You just have to know what 'mor' and 'far' mean and the rest is a piece of cake. (easy)
I envy you, Polly, for having a clue written on the back of the photo. The few photos we have left (after a disasterous fire in my brother's home) name neighbors and animals (such as Glory, the horse)but not the family members. I suppose they thought everyone knew the family members. :-)
Judy