I have 10 raster images (.tif format) with no spatial reference system (SRS). Is it possible to mosaic them by taking into account that they do not have a SRS?
First of all you must make sure all 10 images are referenced one by one the most accurate way. After that you should visually check if it's all right. If it seems fine just then you should Mosaic Raster. I suppose you might get errors if accidentally one ore more blank spots are created after georeferencing.
P. S. Maybe it is worth to have separate 10 images. And work with them as a group of elements in the Table Of Contents. In that case they are slightly smaller (by size, not dimensions). Zooming & panning works faster as well.