Samuel Klein, 17/11/18 16:37:
Much of this seems to be the size of images; there are other creative ways (selection of images by priority, size proportional to priority) to reduce those
I remember that Kelson explored various JPEG quality levels back in the day. The widest discussion about image compression that we had recently was perhaps for https://www.mediawiki.org/wiki/Requests_for_comment/Reducing_image_quality_for_mobile.
Federico