Currently it's possible to upload a photograph as a png image and include it in the content. This results in serving an image to the users which looks exactly like the jpg would, but is up to 20 times larger (~100KB jpg vs ~2MB png ), and so has a large impact on page loading.

This seems to happen very frequently. We can scan our content for any png photographs being used, and hand the list to NROs so they can reupload the jpg version. We could have the script check the file size of each (e.g. only report over 100KB), so that we can filter out icons which shouldn't be an issue.