It handles image loading, unloading, and basic manipulation options.
I imagine, especially if the traffic is mainly for downsampling, it'd be sufficient. If it's not, then writing some custom code to do the image transforms on a GPU and bring them back shouldn't be that gnarly--and if you can afford to stick a shitton of macs in a data center, you can afford a graphics programmer to get that done.
Then again, one wonders why not just use FreeImage or something?