Program needed to edit dds file

Don't have money for photoshop, any other software out there for this, even freeware.

Just need to edit dds files for making mod in oblivion to add armour to drop after level 30, already have best armor for last 17 lvls am lvl 37, be nice to add new look to armor I am creating, just dont think any of my old programs (that I have to dig through cds to find) will work anyway.

Thanks in advance.

gimp works, and got a dds plugin. Am good to go, modding here I come.

ps. I know some say modding is like cheating, but I am the arch mage, fighter's guild master, arena grand champion, so having better armour drop instead of buying it in the store or just giving it to me is cool.