First, log into your account.
Then, on the Control Panel, click on "My Photos." Since this is your first time uploading a photo, you'll need to create an album for it, so click on "add one", located just below "Photo Albums.
Name your album, and post some information about it, then click "Create."
You'll go back to the My Photos" area, although now your album is listed, and there's a slot on the left that says "No Picture." Click on "No Picture" to come to a new screen
At the top of that screen you'll find a tab labelled "Add Photos." Agree to the condition, then find whatever photo it is you wish to upload from your computer, click "Upload", and you're done. Note that only jpegs, gifs, and png images are allowed. Also note that users with Internet Explorer can not upload pictures for some reason (but they should be using firefox anyways). Furthermore, even if you post in one of those formats the site will occasionally say it failed to upload. Don't believe it: your picture likely uploaded just fine if you followed all of these steps.