quicktime picture attachments

Hi there.
I wonder if anyone can help me. I have a problem when I recieve email picture/movie attachments on emails at my yahoo email account. The attached files are mainly jpegs and movie clips and when double clicked are opened up by 'quicktime picture viewer' to be viewed, but there is no image, just a blank black window. Yet if i go through the process of saving them somewhere and opening up picture it express for example to view the saved image it works fine. Is there anything i can do to make picture viewer actually produce the image on screen or is there something better than picture viewer that i can use just to quickly view an attachment then close and go onto next email ?
Any ideas ?

Cheers

Geordie