When you have a huge list of bookmarks in the Bookmarks menu, then it might become difficult to quickly find the bookmark you are looking for. So adding a menu-item icon to bookmarks might be useful to visually structure the Bookmarks menu:
In the Edit Bookmark dialog please add a button with a drop-down menu to select a 16x16 icon for this bookmark. The drop-down icon selector menu could be filled from a user directory of 16x16 icons (PNG, BMP).