Yes Extra images can be added to Stellarium. How this is done depends on the version you have. Adding images is quite a time intensive procedure as the images need to be processed to a square of sides 128, 256, 512, 1024 pixels. The size needs to be known to arcsecond accuracy and also the position. There is no dynamic method of doing this at the moment and adjusting textures to suit the screen overlay can involve hours of work loading and unloading Stellarium while adjustments are made.
The current version still under development has a new form of displaying textures that basically relies on knowing the coords of the corners of the image and is being developed to allow automatic downloading and mounting images from the DSS.
You apparently have the the 0 10.0 beta version which uses the later form for images. I have made some extra images to add to the existing list. These can be downloaded from my Stellarium web site
www.geocities.com/wendygblyde
Barry
