Systems, methods and apparatus for processing image data are described. One example method includes performing a conversion between a visual media file and a bitstream. The visual media file comprises image items each comprising a sequence of pictures according to a media file format, and the bitstream comprises access units each comprising one or more pictures each belonging to a layer according to a video coding format. The media file format specifies a suggested transition period of an image item to be applied for a transition between the image item and a next image item during displaying of the pictures as a slideshow.