Problems With Color Aerial Photos on Mapserver

Has anyone had the following problem???

I have uploaded a new layer of aerial photos using our Mapserver
application. The Tiff files were preprocessed using ECW compressor
before loading. The compressed version of the photos are just as clear
and the color is as perfect as the originals, but when viewed in the
application the colors are strange. Its very hard to describe but they
look "blocky" and not very sharp...

I would appreciate any feedback.