Good points ppcfanatic,
Here's an idea of what you can do, Webdev. We keep pushing ezinearticles.com right? OK, first let's break it down to people you are targeting...
1) Myspace users
2) Bloggers
3) People without a web host
Let's start with MySpace users.
Ezinearticles has a category for social networking sites...
http://www.ezinearticles.com/?cat=In...ial-Networking
Think of a topic you could write about that will help MySpace users and then find a way to work in a RELEVANT mention to your pic upload site. Ezinearticles will actually let you link to your own site in your article (read their rules before submitting)
Writing articles is one of the fastest ways to start getting traffic but you have to do it regularly and be somewhat creative about the topics you choose.
For example for my flat stomach site, I just submitted an article today about the connection between self esteem and weight loss. This is one of many articles I've submitted at ezinearticles. One article I have there has gotten 38,000 views and 28 people have published it in their ezine (ezinearticles reports your article stats so you know how many views it's getting.) Over time little things like this start to build your traffic.. But you can't just do one article. Keep doing it.
And if you don't like to write, your articles don't have to be very long and drawn out. The minimum is only like 250 characters. So it can be very brief but make it useful so people will want to link to it from their ezines. Don't just write junk.

What can you talk about related to picture uploading that would make other webmasters want to use your article?
And if you do plug your site in your article (and not just your sig) be careful it doesn't come off as too self promotional or they'll make you take it out.
When you have a small site like that with very little content you are going to have to come up with some creative ways to advertise it. Submitting articles is a great way to start.
Notice a theme here? It always comes back to writing content doesn't it?

No matter how you look at it you have to do it whether you're adding it to your site or using article submission sites.