Communication terminal, image data communication system, and communication method

An image data communication system, comprising:

• a first communication terminal including first circuitry;
• and
• a second communication terminal including second circuitry,
• the first circuitry of the first communication terminal being configured to transmit a plurality of pieces of image data and layer display order information indicating a layer display order in which a plurality of images represented by the plurality of pieces of image data are to be displayed on different overlapping layer levels on a same overall display region such that when a region where display positions of at least two of the plurality of images overlap with each other, an image from the at least two of the plurality of images with a highest layer level is visible in the region,
• the second circuitry of the second communication terminal being configured to display the plurality of images represented by the plurality of pieces of image data transmitted from the first communication terminal in the layer display order based on the layer display order information transmitted from the first communication terminal.