Corel Instant Viewer slow opening.

[Cereal]

Greetings. For some unexplainable reason some .jpg files open slower than others. To elaborate - I have several folders filled with different bmp/jpg/png files (wallpapers, print screens, photos etc) and whenever i open some picture using instant viewer it usually loads in a matter of seconds along with the rest of pictures in a folder. Today i found several folders filled with identical (taken from 1 source) .JPG files that literally take forever to load in instant viewer. I have tried renaming them, changing extension, re-saving, moving to different folders - nothing helps. All of the pictures are well under 1mb and they all seem to be simple jpeg files. I realize that something could be wrong with pictures but they do open just fine and pretty fast in other viewers and programs.