Quote - When I choose anything other than tiling for the Image_Mapped field, I either get a blank white screen or, if I choose Clamped, I get a screen filled with the edge pixels of the loaded screen image.

That's a clue. I'm now ready to guess that the prop UV coordinates are outside the range of 0 to 1. In preview you've lined things up, but in rendering, the actual coordinates work out wrong.

The original image is coming into the right place because it is tiling from 0 to 1.

Whereas your cropped image is tiling from some subset of that, and then mapping that onto the 0 to 1 as well as everything more than 1 and less than 0. But outside the 0 to 1 range, it lines up differently. If the prop were displaying the base UV unit (0 to 1) it would match the preview. It doesn't match - ergo it's not in 0 to 1.

If that's not clear, visualize this:

Tile the original image and your cropped image - imagine an infinite sheet of those.

Now visualize the laptop screen as a window, moving around on the infinite sheet. It moves always to a whole square, bounded by multiples of 1. On the original image sheet, all those other squares are identical to the home square. But on the cropped image sheet, those other squares are not identical.

The screen is showing (mapped onto) one of those other squares, not the home square.

Is this a free prop that we could go get and look at?

 

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)