MS GeoGraphics used to have seamless mapping of raster images (see attached image).
How do we do the same with Ustn SS2 + Bentley Map SS1?
Raster Manager doesn't support seamless mapping, or more accurately, not completely. All file attached in Raster Manager are kept opened but the pixels of a raster file is only loaded on demand. All raster files attached in Raster Manager are sharing a common memory pool whose size is usually limited to a fraction of the available memory. This is why very big raster file (many gigabytes in size) can be easily handle by Raster Manager. In fact, there is no know limit of the size of the raster file that can be attached in Raster Manager.
But there is a limit on the number of raster files that can be attached in Raster Manager, whatever the size of those raster files. The limit is caused by the fact that Raster Manager keeps all raster files opened, which required some memory (no more than a few megabytes per file). So the number of files that can be attached in Raster Manager is directly related to the memory available on a computer. I would say that a few thousand raster files could probably be attached in Raster Manager on a not too old computer.
So, is it why you want the seamless mapping, because of have too much raster files and all of them could not be attached in Raster Manager at the same time?