I want to put a picture on my profile, but I have no idea how. Does anyone know how to put on on with moblie?

First, you'll need to upload your images to an image hosting site, like imgur, get the URL for the image, and then put [img]image URL[/img] on your profile where you want the image.

(it should be noted though that the profiles do not use some of the same codes as the forums- they do use the same code as the PM system, though, so you can go to "Compose" in the PMs with no recipient and type out your profile so you can preview it.)
(the differences are just relatively minor differences in the tags, like image linking using "imglink=" instead of just "img=", and font colour adding "#" before the colour hex)
(why do they use different codes? I don't have a clue, but they do)