See if this matches what you are experiencing: Pasted images not appearing via IWP
This is one of many acknowledged bugs that can be found in the Known Bug List here in the Report an Issue section of the forum.
It can also be downloaded as a database file from: http://www.4shared.com/file/8orL8apk/FMP_Bugs.html
After serval trial, I find that if you save the image by Mac OS Preview utility to pdf format. And reopen it, select all, copy it, and past to FMP. The image can be displayed. Fyi, I am using FMPA 11.0v2 and Mac OS X 10.6.6.