Hi, and welcome to the forum. Why don't you tell us a bit about yourself?
To post photos - when you want to reply or post you will see 'additional options' below the white box, click on that to 'attach' a file. Click on choose and find your photo - they need to be fairly small so I put a reduced size copy of a photo on my desktop so it it easy to find, click on the photo you want, it will add the code to your reply/post, then click 'post' at teh bottom of teh window.
Avatars are really small so you need to reduce the photo you want to use first. Then go into your profile, click on forum profile information in the modify section. You can upload your avatar from there.