Minimize image map resolution. The maximum size needed for an image map used in a RenderZone material is determined by the percentage of area the material is visible in the final rendering. For example, if you RenderZone render your scene at 1000 x 1000 pixels and the image map material takes up only 25% of the final rendering then any resolution greater than 250 x 250 is not necessary, (1000 * 0.25 = 250).
Image maps loaded into form•Z are converted and embedded into your file based on their resolution, not the size of the file on your computer. Image maps used in RenderZone materials are still embedded for Shaded rendering modes and the external link is used for RenderZone rendering.
Memory used for an image map is always squared to the next highest power of 2, (512, 1024, 2048, etc.). For example a 1000 x 800 pixel image will have approximately the same memory usage as a 1024 x 1024 image. And a 1030 x 1024 image will have approximately the same memory usage as a 2048 x 2048 image. Each material displays its Memory Usage in the Color Map Options dialog.
Image maps in Shaded Work and Shaded Full are displayed in your scene at a reduced resolution, which can be adjusted in the Display Options palette.
If you ever have rendering irregularities with long slender image maps, (i.e. banners), then resave the image with a more square ratio by adding additional blank space in any image editing software. For example, if you have a banner image that is 50 x 2048 and you see some rendering irregularities, then resave the image as 2048 x 2048 with any color for the additional space. Note, the memory usage will be the same and you’ll need to adjust the texture mapping so you don’t see the additional blank area.