Overriding THUMBNAIL_EXTENSION = 'webp'

[stephen-calm]

I have set THUMBNAIL_EXTENSION to 'webp' and this works for the entire website which I am quite happy about, but on occasion I want to either preserve the format uploaded or change it to a different format. An example of which is OG Image which dosn't support webp and needs to remain png.

What I am looking for is what template tag option do i use to change the file format, and if there isn't one how do I extend the functionality to allow it to do it or failing that is there a third option?