I have a JPEG image of a map which I need to georeference. But first (I believe?) I need to give it a spatial reference. I used Define Project to give it WGS84 (which is the spatial reference of my other data). However, after I used Define Project, this is how the raster image shows up.
You don't define the coordinate system of the raster that you are trying to georeference. There is a procedure outlined in the help topics... Fundamentals of georeferencing a raster dataset—Help | ArcGIS for Desktop