Initial image full screen width and height

I have been asked to create a webpage where the initial image is the full screen width and height, there is a horizontally centered piece of text 1/3 down the screen then a 'scroll down' text horizontally centered and 10% from the bottom.

The rest of the page is a standard webpage and I envisage the initial full size image to be a slider once we have some photography.

Also, what size would you recommend the main image be, looking at the stats for the current website most people are on 1280px ish but 3% have huge monitors.

Thanks