Joho,

very good analysis. Google Earth uses the maximum texture size that the graphics card reports that it's capable of. If you supply a larger image, we reduce it to fit within that - why the 2300 x 2300 overlay worked on a card that could only handle 2048 x 2048. The only caveat is that the image is downsampled so the quality is not as high.

On other cards, they report a maximum texture size bigger than they can handle. So although the card claims to be able to do 2k x 2k it can't. The workaround in this case it to reduce the texture size to 1k x 1k which virtually all cards can support. We have a mechanism by which we can identify and artificially limit the texture size on problem cards like this. When the next release happens, we will be doing a lot more testing to fix problems like this.