I have an image mosaic of ~150 TIF files and when I mosaic them it works fine. But when I turn on the mask - 255, 255, 255 to show as no color, i get these strange white lines appearing. This only appears when I am zoomed out, but as I zoom in it seems to disappear. When I identify these spots, they are truly 255,255,255. How do i get rid of these. I have tried various tools, including, define overviews, build overviews, calculate statistics, and Define NoData. None of these options seem to fix the drawing issue. Any help is greatly appreciated.