Selecting a template splits the message area into several link areas, and a different action can be assigned for each area. (Note that templates do not split the design area.) Refer to the design guide when creating an image for each template.
The available templates and image sizes are as follows:
[Available image sizes]
Six image sizes, appropriate for different resolutions and data usage, are available.
Because the in-app display aspect ratio is all the same, you can create and upload larger images that look nicer on high-resolution devices, but because doing so requires more data, the images may take time to load.
* The in-app display frame size is fixed, so small images may appear rough on high-resolution devices.