setImage can display .jpg .gif and .png but not formats .bmp .webp and .avif

No error, just no image shown

Is that just a limitation or can setImage be updated to support other formats? I can work around by converting images with e.g. Paint, but it would be nice if I didn't have to.

Also setImage won't display .JPG but OK if I do .toLowerCase() so not sure if the case issue is just a feature or can be fixed.

Yes, SexScripts accepts only GIF, PNG and JPEG image format. The relevant code inside is

https://docs.oracle.com/javase/7/docs/a ... ang.String)

SexScripts doesn't do much more than passing the name and path of the image to this Java function, so it is a limit (except adding some plugins, but it means bigger release, more tests, work for compatibility desktop / Android, more maintenance and risk of failure like the current state of webcam in SexScripts, etc.)
It seems that the JPEG/jpeg extension failure is an old bug (in Java), perhaps only in some versions of Java and not all. If you do .toLowerCase(), your script will fail on Linux and MacOSX, so you should instead rename tour picture to a lowercase name.