Deleting resized images over SSH?

I’ve seen a number of plugins for deleting resized images that you no longer use, but many of them are rather old, and I’m concerned about the efficiency of php at deleting all these files. Can’t I just SSH and do something like:

rm -rf *-{300x225.jpg,225x300.jpg}

On a related note, I’m trying to cut down, not so much on storage, but disk I/O; it seems to be the bottleneck when it has to resize each file several times. Moving forward I will have only two versions of my images: the original, and the thumbnail. My plan is to rely solely on Jetpack’s Image CDN to handle resizing my images on the fly (the thumbnail copy being for browsing my media library as that doesn’t use Jetpack’s CDN).