Found an interesting clause inside stating that the winners must submit the winning image "....in A3 420mm x 297mm dimension, JPEG, TIFF or PDF file format, and 300dpi resolution on a CD ..."
That works out to about 17 megapixel of image detail. Certainly no camera in the market now has that resolution yet, so software interpolation is definetely required.
Question is: what level of image detail are they looking for eventually? Although online submission only requires 640x480 resolution, can the winner simply scale the 640X480 image into a 300dpi A3 size (ie.4961X3508 pixels)? How about scaling from a 2 megapixel image? Or 3 megapix, 4mega? 5mega? How much is enough?