MPC is known to give some problem or the other with image capturing.. If what RdA suggested doesnt work.. Do try ImageGrabber.. Its worth giving a try.. Somebody above already suggested it to you.. You can determine what size each frame should be in the multiple screenshots you take and add custom information to the image too.. Its a small freeware and is easy to use..
A version 2 is out.. I haven't tried the 2nd version though.. But hopefully it should be better..
Download link:
Code:
http://www.videohelp.com/tools/ImageGrabber
Example:
x|D