You can insert pictures in the questions. Simply insert the image in a paragraph following the question text.
These must be single image files - not images draw or annotated using Word's drawing tools. Picture formats don't have to be web-compatible - for example you can insert clipart and Respondus will convert it to a web compatible format.
The test is loaded into Respondus as a "Respondus File". These files are usually stored in My Documents in a folder called Respondus Projects. Choose "Save" from the File menu to save it. Then you can open it again at a later time (to print or re-load to Blackboard) by choosing "Open" on the first page of Respondus.