Anyone can suggest a new plant be entered into the database, but I believe a moderator has to approve the request. First make sure that the plant is not in the database. When someone looks for a plant and it is not there, often it is a case of misspelling the name while searching. If after searching and you don't think the plant is there, go to the plant database page and you will see a link that says "Add a new plant to the database". Click on that link and fill in the info.
To add a photo, find the plant in the database and look on the left side of the page, there is a link that says "Upload a photo". Click on that, then click on "Upload image", that will open a box showing your computer files. Find the photo on your computer and click open.
