Hi @mdotk
Thank you for getting in touch.
We don’t have UI controls for custom tile servers as it’s not a request we get very frequently at all, in fact I believe you’re the first person to ask this question in some years now at least.
It’s perfectly possible to do this with our plugin, I’d recommend using the OpenLayers mapping service for the easiest approach. It’s also possible with the Google API, however you would require a correctly setup API key from them. Unless you’re going to be using features such as real-world address geocoding, I don’t really see any advantage in using the Google engine.
The biggest challenge to overcome here will be breaking your PNG up into tile imagery for the server to serve up at various resolutions – assuming it’s a very, very large map.
That’s definitely something we can help with if you’d be interested in working with us on that. If so please feel free to continue this conversation here or mail us directly.
Does that help?
Kind regards
– Perry