These settings specify how to handle images imported from drawings created by CAD Overlay GSX or CAD Overlay ESP.
AutoCAD Raster Design toolset handles images differently than CAD Overlay GSX and ESP did. With GSX and ESP, you could paste a main image and up to nine reference images into your drawing. The main image was given the same filename as your drawing.
If you want to open a drawing in AutoCAD Raster Design toolset that you created with GSX or ESP, you can enable an AutoPaste feature that locates and automatically pastes the main image into your current drawing. When AutoCAD Raster Design toolset pastes the main image into your drawing, it also pastes all of the reference images associated with the main image.
AutoCAD Raster Design toolset searches along the AutoCAD project files search path for an image filename that matches the name of your drawing (the main image), but you can select which image types (file extensions) you want it to search for. For more information about setting the project files search path, see the AutoCAD online Help.