http://chevereto.com/ is good. That's what most image hosting sites use or at least start with before they go custom. For example one of the bigger hosting sites ImgCenter that started on KWWHunction started live as chevereto before going custom.

This one is also decent http://www.scripteen.com/scripts/scr...ng-script.html

This is going from memory about 2 years ago when I was looking at them. I haven't worked or looked at an image hosting script since but I'm sure it hasn't changed too much. It's all still about uploading and hosting an image.


EDIT:
What really pisses me off about a lot of the people here is they use a free script like Cheverto and then go and remove the copyright link without having permission. They make a theme which is basically 5 minutes of html and claim it's custom. Load of bullshit. Just stop lying and leave the original copyright link.