I'm looking for something that's (legally) free that can edit massive amounts of pictures at a time, changing general properties. (Resolution, mainly.)

I've got about 200 pictures, and I do NOT want to have to change the resulotions from 1600x1200 to 800x600 manually in photoshop for each one...

Any ideas?

I think if you have photoshop you can record an action of you changing the resolustion down and then apply that to every photo.

Or you can just get irfanview

You could learn python. In my CS class last semester we learned how to write a simple program to do that. I forgot how, and it was insanely stupid to do when you could just use available software, but I thought you could learn how....

If you're on windows irfanview can do that easily (batch conversion/rename is the name of the option, although I don't know where it is anymore because I don't use windows anymore): http://www.irfanview.com/

On linux it just takes a tiny shell script to run them through imagemagick or something.

In photoshop, record an action of the task you want, then go to File/Automate/Batch. Set your preferences, let 'er rip.

That feature right there was one of my best friends when I was doing graphics work for the yearbook last year.

Paint shop pro can do batch processing as well.

Irfanview.