As for placing a JPEG:
Since it is oval, you'll make a new material Using the JPEG as the texture image.
Use this new material to surface the oval.
The oval probably won't exactly fit, so you'll align the texture. I don't have Archicad 13 on right now, but it is probably found under Design>Align 3D Texture> Set origin. OR something like that. CLick around a little and see what happens.
Dwight Atkinson