Digital camera

hello all,
i want to make a digital camera as a project for a competition
please i want do it using Arduino or any other way
thank you all

I'd go with "any other way".

So, I don't have to repeat myself on why the Arduino is a bad choice for image processing, go to this thread: Arduino Forum

First find a sensor. Then figure out how much bandwidth and stroage you need, then decide on processing power.