Hello feiko.lai,
In the version 1.3 it would be possible to export orthomosaic to MBTiles, Google Map Tiles and World Wind Tiles. There's additional argument in the .exportOrthomosaic() function defining the tiled image format. Now format argument defines the high level format (for example, RasterFormatMBTiles or RasterFormatXYZ), while image_format defines the format of the lover level tile format (like ImageFormatTIFF or ImageFormatJPEG).