A user uploads an image and chooses Full Image. Then attempts to downsize it, by clicking the image and moving the corners in (like you do) System is still parsing the BBCode as ATTACH=FULL. So, the full image is being shown in the post. Resizing makes no difference. I've just tried to edit a user's posted image down from full size, resizing it myself to say 500x375 and cannot get the post to resize as it appears in the preview.