still image problems in fcp project

I am a new user of fcp and have found that some black and white still images look good when originally brought into a sequence and I add motion, but over time some of the images will get a shimmer or distortion to parts of the image. Sometimes the motion in the image will be jerky or jittery (like a pan or zoom). All the photos are TIFF''s of varing resolutions or frame sizes. The frustrating thing is, most still photos in the sequence are fine, but some show this problem. I even deleted one and reimported into the project, but this did not fix the problems.

Thank You
Greg Hammons