I'd like to point out that the first post in this thread outlines why icons are optional but encouraged. Your pending submissions page also displays a large "no icon" image so it should be fairly obvious that icons are needed one way or another. They're optional to make the process accessible to as many people as possible but those submitted with icons are given priority.
For reference, you can add icons to your own pending submissions from your pending page by clicking edit.
For reference, you can add icons to your own pending submissions from your pending page by clicking edit.