Today we activated a tool which compresses every png uploaded to your onCourse Website. This happens automatically when you upload the file to your onCourse website and does not alter the quality of the image in any way. Many tools create png files with excess "filler" and our tool cleans that out. We are seeing a saving of 20-30% quite commonly. This means some sites have been slimmed down by 150Kb and maybe half a second in loading time.
Just make sure you create your png files with the lowercase extension .png.
We continue to work on other techniques to make your websites faster, particularly on mobile devices. This is just one step in that journey.