You can never overdescribe the item you are selling. Super detailed descriptions will always equal more sales and/or higher bid prices than if you put a very brief description for your auction.

Likewise, the more photos you have the better. If speed of downloading is an issue, you can include thumbnails that potential bidders can click on to see a larger version of the image in more detail.

If you aren't sure of what kind of description to use, check out completed auctions for the same or similar items. But never copy someone else's description word for word, as that can result in your auction being ended. But reading other's descriptions can get your own creative juices flowing for writing your own descriptions