If Clickfree keeps failing at one specific image, then the next file may be corrupted.
For example, fails at 1218, then 1219 is the image with an issue.
Locate and Delete the image on your phone to continue the backup.
If you still want the image, e-mail it to yourself or screenshot it so that you still have it, and that way the picture format will be changed as well (which also could have been the problem as to why it wouldn't back up that image).