Editing profile picture and sig sizes:

Profile.......Max size is 100x100 pixels or 64.0kb (whichever one is smaller)
Siggie.......Max size is 500x100 pixels or 97.7kb (whichever one is smaller)

How to upload:

1]Goto your usercp page (via link at top of forum homepage)
2]Click on edit profile picture or signature option in the left-hand menu.
3]Here you will have two options to the way you wish to access your chosen picture.

Option 1]Enter the url link from the host site your picture is hosted on(ie;imageshack or photobucket)The url you require is the link for embedding on forums.
Copy and then paste the link into the option 1 space.

Option 2]Click the browse button,which will then open up your pictures file on your pc.Click on the chosen picture and then click open.
This will paste the default hard-drive path to that file.

4]Once either of the above options have been done click on save changes,that should then upload your chosen image as either your Profile Picture or Siggie Picture.

I hope this will help you out m8,if you have further problems feel free to ask for further assistance..."thumbup"