In-place conversion from JPG/PNG to HEIC (or the other way around)

[mbirth]

Is your feature request related to a problem? Please describe.
There doesn't seem to be any way to convert huge PNG or JPEG files to HEIC without having to export them, doing the conversion outside of Photos and reimporting them - losing album memberships and non-destructive edits in the process.

Describe the solution you'd like
A way for osxphotos to either allow running commands (sips -s format heic ...) against photos in the library - updating the file in the library with the result of the operation. (Also accounting for changed file extensions!)

Or, alternatively, a way to replace existing photos on import while keeping everything else in the database intact.

Describe alternatives you've considered
I've searched for plugins allowing this, however, it seems that plugins merely get the plain image data to work on without having any influence on the format.

The only working alternative at the moment seems to be the above mentioned export-convert-reimport followed by having to sort everything back into their albums.

Additional context
For bulk operations, maybe add a flag --only-if-smaller to only replace photos if the converted version is actually smaller in file size than the original.

See also: https://apple.stackexchange.com/questions/395555/is-there-any-way-to-have-macos-photos-bulk-convert-all-of-my-past-jpeg-images-to

[RhetTbull]

See #909

This is a planned feature but not sure when I'll get to it.

[RhetTbull]

Also, osxphotos already contains native code to convert HEIC to JPEG. This can also be used to go the other way so there won't be a need to call sips.