Often when I edit a texture the preview thumbnail turns in to a black and white gradient, like this:   In this case, it happened when i duplicated Brown-Dark to make Brown-Medium. The colours render fine in the model but not in the resource browser. The textures are basic color shaders with no reflectivity, transparency or bump indicated.   The texture itself still works, but the preview does not. Restarting has no effect. Couldn't find any posts about this on these her