The point is that with a CCD array you have to read it out as fast as possible to stop the image degrading. There are several ways the array can be built to minimise this but in essence unless there is a mechanical shutter you will get some image degradation. The arduino communicates with serial data, do the maths, look at the fastes speed this will go at, divide by ten because it takes ten bits to transfer a byte. Then multiply that by the number of pixels and you will see how long it will take to transfer an image. My guess it will be measured in hours.
OK just done the sums on a 3032 by 2008 image at 115200 Baud works out at just under 9 minutes.