Hi newt,
This is indeed turning into a ridiculously difficult project.. you'd think something so basic would be universal after all these decades...
Currently my mailto URL works on the device in chrome, or as an app (cocoonjs) BUT refuses to work now in safari even though it did once, but never again even though I changed nothing...sigh...
Also, It seems the MUST HAVE EMAIL ADDRESS rule is no longer true, as it worked at least on chrome and as an app with no email.
I'll report back if I figure out a truly universal solution.
Can you please explain how to include an image?!? That would be cool... but of course, if it then breaks on many of the platforms its most likely not worth it...I'd still like to give it a shot though.,