If you are using Raster Design, there is a drop down menu on the "snap" panel of the ribbon. In it there is an option to "shift+left click to select image". Turn it off.
In Civil3D (and I suspect AutoCAD Map), the same option is available in the map options box (command "MAPIOPTIONS"). One of the tabs has a checkbox for ""shift+left click to select image". Uncheck it. You need to do it both places, as I found out today, if you have C3D and RD.