Trouble with Clipping mask .... just wanted a Moodboard

[Amelie5ECE]

Hey guys i would like to do a basic moodboard in Illustrator!!! therefore i put a black shape in the background und put the picture i would inside the shape in the foreground. Then i select the shape and the picture and go to clipping mask (cmd+7). Illustrator is telling me that i won't work but why ? what am i doing wrong ? maybe somebody can help me xoxo

[c.pfaffenbichler]

If I understand correctly the path should be in front of the image. 

Otherwise please post screenshots including the pertinet Panels.