According to the rule, me should be used in the sentence above because the pronoun is not the subject of the sentence (it can be considered the object of the preposition of). According to the rule, the caption should be rewritten as "This is a picture of my best friend and me at a basketball game."
Grinder starts with grin-, and grouchy starts with grou-. You need to find a word ranging from "grindeq" to "grouchx", and the only one on this list is gripe.