I have thousands of old photos that preview can open, but I can’t upload them into the photo.app because the file format is wrong. I’m going to try and use SIPS to convert them all into png first and then add to photo.app. Thanks for this pointer.
sips looks really cool, thanks for pointing this out.
Not gonna lie, I missed this because I thought it was related to macOS SIP, System Integrity Protection. Which is something I am deeply uninterested in.