I'm currently using the convert command as part of ImageMagick which works fine on my RaspberryPi but is very slow, that's no surprise since the RPi is low in CPU power and the images are fairly large.

Anyone know of any command line image conversion packages for Linux? Everywhere I look seems to recommend ImageMagick (understandable since it works absolutely fine). Can't find any reasonable alternatives. ImageMagick might well be the fastest package out there for the job.

Pretty sure imagemagick is the best you're going to get. Only other one I'm aware of is GD but that's just a library, you'd have to hook into it from something else (and I suspect that'd be slower).

I thought as much.

I've asked over at the Raspberry Pi forums to see if it's possible to involve the GPU and one of the main developers is looking into it.