What does the creature do with the portrait he takes from William?
Does he break it or frame Justine with it, im not entirely sure.
Its in chapters 15&16 Of the book Frankenstein, and i keep re-reading it over and over again and i still cannot seem to find it. guess im blind ^-^
The answer that you are looking for can be found near to the end of Chapter 16. After the creature takes the locket with the picture in it from William, he uses it to frame Justine -- to make it look as if she was the one who murdered William.
The creature looks at Justine as she sleeps and sees how lovely she is. He thinks about how no one like her can ever have affection for someone as grotesque as he is. This makes him very angry and he resolves to punish her for the fact that people recoil from him.
Because of this, he puts the locket in her dress, thus making it look as if she killed William. Here is a quote showing this:
not I, but she, shall suffer; the murder I have committed because I am forever
robbed of all that she could give me, she shall atone. The crime had
its source in her; be hers the punishment! ... I bent over her and placed the portrait securely in one of
the folds of her dress.