kev's right!!, image planes are huge system hogs even when i had a 2 gig and a 32 mg ati all-in-wonder card, the image planes moved slow.. but did not take five secs... till i upgraded to a 2.4 with a 128 mg Ti4600 it moved more smother... what i am trying to tell you is img planes are heck a system hog.. as kevin said...

Here's the instructions for making a polygonal plane:
Click Create -> Polygon primtives -> Plane

Now rotate the plane to whatever position you want... then right click the object click assign material - > material attibutes click the checker beside the color section.. then choose file, then choose the image you want the plane to show.. after you have done that,

in the viewport panel click shading -> Hardware texturing

make sure you are in smooth shaded mode or else you wont be able to activate the hardware texturing mode..

Tariq