Hahaha...
The 'dumb' way is only slow if you don't have hardware overlay planes on your video card. The very cheap but decent VX1 card handles them perfectly well (if you don't enable transparency or gain).
You can set the transparency of an image plane in the display part of the attribute editor with the image plane tab.
To delete them, either go into attribute editor and with camera selected, click on image plane tab, and press "select" at the bottom of the AE, and then press delete...or just open up the Multilister or Hypershade and delete them there.
I prefer the camera image plane way - I don't need to turn on hardware shading to use it (so I can model with wireframes which makes many things easier...like being able to see your image!). When you are matching live plates, you only have as much room as there is between your mapped plane your camera...with image planes you can have as much space as you want without having to increase the size of the plane or the image res. Suppose something has to move from very far to very close? Sure you can cheat with scaling but isn't easier not to? And when rendering, you can use the "use background" shader on floors and so on to compare your shadows with live elements.
10 PRINT "kemijo is the best"
20 GOTO 10
RUN
