Apple watch complication to show image from URL

[michaelblight]

Is your feature request related to a problem? Please describe.

Some watch complications can show images (eg. CLKComplicationTemplateExtraLargeSimpleImage). However, in these cases, the app only shows the icon in the place of the image.

Describe the solution you'd like
I would like to be able to provide my own URL for the image to be displayed. There would also need to be some way of triggering updates to the image (eg. refreshing periodically).

Additional context
I'm actually wanting to display a weather forecast for the next week. It would be nice if I can do this using HTML, to be rendered on the watch as an image. However, using an image works too, as I will just do the conversion on the server.