Formatting in Gimp 2.6

[Superannuated]

I know this may seem irrelevant to anyone with advanced skills, but I could really use some help. I need to format some portfolio photographs for an online webservice which manages national public Art competitions. I've used the recommended Photoshop Elements 8 before and followed the tutorial and acheived good results, but my computer crashed and I lost that program.
Now I have Gimp 2.6, which should be able to do the same things re: image size, background, file size, etc. Can anyone give me a "step by step" for Gimp 2.6 that parallells Elements 8's video below:

http://www.zapplication.org/videoPlayer/player.php?file=/videos/PhotoTutorial2.m
ov&height=420&width=600&frontcolor=0xe9e9e9&backcolor=0x333333&lightcolor=0xffff
ff&showdigits=false&showvolume=false&autostart=true&type=flv&usefullscreen=false