cover_url = ctx.files_path + urllib.quote(cover_url[7:])
IMG_EXT = ('png', 'jpg', 'jpeg', 'gif')
if '.' not in cover_url or cover_url.rsplit('.', 1)[1].lower() not in IMG_EXT:
cover_url = ctx.files_path + urllib.quote(cover_url[7:])
IMG_EXT = ('png', 'jpg', 'jpeg', 'gif')
if '.' not in cover_url or cover_url.rsplit('.', 1)[1].lower() not in IMG_EXT: