I've seen many post questions like "How do I put up am image/av under my username?" "How do you put in an img into your sig?" "How do you...???" etc. etc.
Here are some tips, if you still have problems regaring avatars and signatures, please post in this thread, don't make a new one.

---Avatars---
Regarding how to put up an av:
1. Go to My Controls at the top left of the window.
2. Click on Edit Avatar Settings below Personal Profile.
3. Choose either one from the gallery this forum offers, link to a pic within the size restrictions, or upload one from your computer.

---Signatures---
Regarding how to make a sig:
1. Go to My Controls.
2. Click on Edit Signature below Personal Profile.
3. Start typing.
Regarding size:
For images, please do not exceed 561 x 200.
Regarding how to put in an img:
1. Have the img ready at hand.
2. Host the img. Here's a useful site for you to upload your images online: Image Shack
3. Paste the link into your sig, it should show up if you have the right link.