IMAGEFRAME system variable
Function Description:
The IMAGEFRAME system variable is used to control whether to display and plot image and map frames.
Type : Integer 
Saved in : Drawing 
Initial value : 1 
Range : 0,1,2
System Variable Value:
0 : do not display and plot image frame
     It may temporarily display the frame when previewing selection or selecting objects
1 : display and plot image frames
2 : display but do not plot image frames