Hover over 'Registered Area' in the Navigation/Menu, (left column) and select the 'Edit Your Profile' from the Sub-Menu Selection.

Click the 'Avatar' Tab

Select 'Upload new profile image' from the Select List.

Browse to your Avatar File in the expanded 'Select File' Field.

Your Avatar will now be a Site Wide Avatar that will appear in the Forum.

If making a comment could you please copy and paste, (or type), the Category Name into the "Title" Field.