Caching an image without displaying it

[David Engster]

Is it possible to cache a scaled image for later display on a certain
frame?  My problem is that scaling images to a certain width/height
through the imagemagick support is not terribly fast[*], so I'd like to
cache the images beforehand. I know I can cache them by simply
displaying them all successively, but I want to do this invisibly
through an idle timer in the background.

-David

[*] Yes, I tried setting imagemagick-render-type to 1, and it helps a
bit, but I'd really like the display of the images to be pretty much
instantaneous.