The idea seems like a good one but you are not solving any problem, it is just a cool way to discover photos on twitter. If you have 6 millions unique users, can you charge businesses to feature their photo on the home page and charge per follower you give them?
The problem with php is that there is no central registry where you can submit your own module like Ruby gems and npm registry for node.js. It feels like you have to reinvent the wheel every time you work on something new...