Unless you got some phot editing programs on the phone, you'll want to use a computer. When I'm trying to get a picture ready for various sites to be used as an avatar, I just use Microsoft Paint. It comes already installed free with windows & can do everything I need.

Open picture in Paint

(Depending on windows version, you can zoom in / out to view better)

Crop the picture by using the selection tool, & move what you want to save to the upper left.

Adjust the rest of the picture to crop down the size, by moving the corner dots

Resize the picture to the size allowed by FA or other site. All sites will have different requirements for Byte size &/or pixel size (FA needs them to be under 55kB & 100 X 100 pixels)

Well I have a Mac so maybe preview or something else will work for me.

Possibly. My mom's got a Mac & several of my friends. I've always stuck with what I know to do picture editing. There might be a program that can be downloaded for iPhone that'll let you edit them.

Let me know if you get it figured out. You might try a google search to see how to easily edit a picture (set pixel size) on a Mac & see what you come up with.

Pictures need to be 100x100 px.

I'm not sure how to change the size on a mac....

Sorry I've been out storm chasing all day so I haven't replied. And I'll google and see what I can do. Got some awesome pics today. Thanks y'all.

Don't worry. When storms call you have to abide to their calling. xP

And you're welcome.... I'm sure you'll figure it out. Search something like how to edit photos on a mac and then learn the software on youtube or something.