Signature Help

[sardine]

Hello, I hail from ChickenSmoothie. Just joined today, and wanted to edit my signature. However, when I paste the code, this shows up.
However, when I just type in random text, it works.
Is this because I just registered today? It also won't let me post images.

[Startedraining]

The first few posts you make are set to be approved, after you make 2 more posts you should be able to add a signature with no problems~

[sardine]

The first few posts you make are set to be approved, after you make 2 more posts you should be able to add a signature with no problems~

Thank you!

EDIT: I made 3 posts in total, but the error still occurs? Is there a limit to images in a signature? I didn't go over the character limit.
The signature I'm trying to insert is supposed to look like this:

(Click for full image, since this is cut off).

[Giant Talking Banana]

What are the dimensions of your signature? If it's too wide, then it will get cut off. Make sure your signature is less than 400 pixels tall and 700 pixels wide.