Say I have images in my WordPress theme that I got from Unsplash or Pexels a year or so ago, when their license was more permissive (GPL compatible).
Fast forward to today: their licenses changed.
Do I need to update the license on my theme for these images, or do the old license for these images still apply (since I've downloaded them at the time where their license was, say CC0)?
I get that with certain OS libraries you can just use the version where their license was different (v1.0.0 was GPL, but v2.1.0 is MIT), but with images, it's a bit different since it's still the same image (no versioning aside the date of download).
Are license changes in this case retroactive?