Hi and welcome to the forums. You can find info about changing your avatar (pic under your user name) in this thread
To add photos to a post:
Click on reply and scroll down to bottom of text box.
Click "go advanced" add text to message window and then scroll down.
Click "Manage attachments" A separate window will pop up.
Click "browse" Then select the file to be uploaded. Be sure that the photo is appropriately sized. 1024 x 1024 pixels (or smaller) and no more than 300 K. You may select several photos to upload at the same time by repeating the last step.
Click "Upload" After pics have loaded close the pop-up window
Click "submit reply" to mount the text of your message - photos will automatically appear in post.