The scroll sync seems to keep the left and right pane in sync by keeping both sides at the same percentage scroll. Unfortunately, this strategy doesn't work particularly well once images have been inserted into the content. I recommend (and may eventually try to contribute) anchoring both pages so the top line of both sides is the same. That will ensure that the preview pane scrolls quickly over images and slower when the text is the same line-by-line.
The scroll sync seems to keep the left and right pane in sync by keeping both sides at the same percentage scroll. Unfortunately, this strategy doesn't work particularly well once images have been inserted into the content. I recommend (and may eventually try to contribute) anchoring both pages so the top line of both sides is the same. That will ensure that the preview pane scrolls quickly over images and slower when the text is the same line-by-line.