Well, we have a conflict in information on the same site then. This is from the FAQ page on uploading photos:
"Furthermore the photos need to be bigger than about 800x600 pixels. We suggest using sizes around 1000 pixels in width. Anything bigger than 1600x1600 will automatically be resized. For portrait format photos we recommend the longer side to be 800 pixels at least."
Based on that information, I've been saving my images at 1000x600 for a long time and while I haven't submitted any lately I didn't have any problems with those I submitted in May. To go back and have to resize hundreds of images to 1024 by 768 is extremely time-consuming and not worth my time. I don't recall seeing any official pronouncement from Johan changing the minimum size requirements either, which should be done for those of us who submit smaller than 1024x768. The above FAQ should also be changed if the 1024x768 size is going to be enforced by the screeners and a several month grace period should be implemented for those of us who have already sized our images.