Hi, I just picked up a 7290 as well.
The only software I've found so far which allows direct transfer from the PC to BB via USB was GTPhoto. I've downloaded the demo and gave it a try...it's straight forward and easy to use. Problem with the demo is it only allows you to preview the image on the BB, but it doesn't save it to memory. The full version of the program costs $20.
I'm not sure if there's any freeware that will do this, but here's the link for GTPhoto, GTPhoto for BlackBerry