1) Click 'Manage Categories' under the 'Lists' heading of the 'Control Panel'.
2) Under 'Existing Categories' select the category you'd like to add keywords to from the dropdown menu.
3) Click the 'Edit' button.
4) Click the 'Image' tab.
5) Click the 'Choose File' button and open your image file.
6) When you are finished, click the 'Save' button.