Enhancement request: Add text fields to SSTV transmit image

[gregoryfenton]

Could we have some text fields in the SSTV transmit functionality that may be populated with callsign, signal report etc and have them overlaid onto the image to be transmitted?
I know we could create a bitmap with that information easily enough while attached to a computer but sometimes we are in the field (not at the moment, we are all locked down looking at github :p)

[furrtek]

Could be done without too much trouble if images are kept in bmp format.

Compressed formats would require the image to be decompressed (to a raw file, not to RAM because there wouldn't be enough), modified, and recompressed -> lots of work for something that could be done beforehand on a computer (except for the signal report of course).