There's also a plugin that uses it here https://github.com/matyalatte/Blender-DDS-Addon. Maybe you could work in dll to allow automatic exporting from plugin if it detects a png instead of a dds. Or hook into the plugin if it's detected to be installed.
Is your feature request related to a problem? Please describe.
BC7 dds don't export
Provide details on the proposal. There's an external dll here for texconv that allows you to export bc7 dds if wanted. https://github.com/matyalatte/Texconv-Custom-DLL
There's also a plugin that uses it here https://github.com/matyalatte/Blender-DDS-Addon. Maybe you could work in dll to allow automatic exporting from plugin if it detects a png instead of a dds. Or hook into the plugin if it's detected to be installed.
Is your feature request related to a problem? Please describe. BC7 dds don't export