I didn't just mean the priorities in principle, but also the technical question which size overrides in case the image is put onto the page with a pixel size specified, because there are a TON of galleries with that, both on artist's wishes as well as mere aesthetic page formatting reasons. So if the page directive for sizing overrides the template directive thousands of image sizes would need to be hand edited on explicit images for the policy to affect them. Similarly, if the image template overrides the page specific formatting, there are potentially thousands of places with broken layouts.