I found out that installing Raster Design Object Enabler for Map 3D or Civil 3D allows MrSID images to be inserted directly into AutoCAD through Map 3D’s image insert command (MAPIINSERT). I use it to directly insert georeferenced ortho photos in MrSID format into my drawings. This is really nice because instead of using another piece of software to cut out the ortho to insert, I can directly insert the lightweight MrSID image directly and clip it to my desired area.

I even created a button with a macro to automate the insertion and clipping of the ortho photo:

^C^Cfiledia;0;cmddia;0;-LAYER;N;Z_ORTHO;S;Z_ORTHO;C;1;Z_ORTHO;P;N;Z_ORTHO;;MAPIINSERT;S:/DATA/ortho/cortho2005.sid;Y;ZOOM;E;filedia;1;cmddia;1;-LAYER;S;0;;(ssget "x" (list (cons 8 "Z_ORTHO")));DRAWORDER;P;;B;(alert (strcat "Pick 2 points to draw a rectangle in the area you want to show the ortho photo."));IMAGECLIP;P;N;\\^C^CZOOM;E;(alert (strcat "Click on the RED box to make the photo appear. Otherwise hit ESC a few times."));\MAPISHOWIMAGE;