Have you tried using this plugin https://www.ads-software.com/plugins/media-library-assistant/

Or you could also try this https://www.ads-software.com/plugins/auto-image-attributes-from-filename-with-bulk-updater/

Just change the filenames of your images then it will automatically change the titles and alt texts of the images based from it’s filename

Let me know how it goes.

I’ve updated them in my media library but the images posted onto my site haven’t updated…

Do you know if there’s a way for them to refresh?? So that I don’t have to go through my whole site and change them again.

Thank you for your help!