[eluser]Mirge[/eluser]
I actually love the Image_moo library. I've used it heavily for watermarking and image resizing (generating thumbnails, small, medium, large, original) for a client project that I'm still working on.
Best practice is to generate your resized copies on upload. You'll waste precious CPU if you're resizing every time on demand. Or if you're resizing once the first time it's requested, I'm sure that'd be fine too, but the OCD in me says just resize the image when you have it & be done with it. Cleaner.
