How add a Raster PNG image

[juangilgithub]

Hi,
I am trying to use a png image as raster with Mercator projection as temperature information.
The image is 512x512 pixels and in Mapbox you can use it as layer over the globe.
How I can do the same with WhirlyGlobe.
Is the same case as Saildrone with temperature map.

I have attached the image I'd like to use as a weather layer.

Thanks!!