Assuming you're alright with clearing the entire attachment field, you should be able to do this with Automations relatively easily.
Make a formula field that'll check whether today's the same date you want the image to be deleted on, make the automation trigger off that field, then do an "Update Record" action, add the attachment field then leave it empty like so:

This'll clear out the image. I vaguely recall reading that deleted attachments still contribute to the file size though as they're kept in the trash for you to recover it or something? Not sure I'm afraid, sorry
Thank you, I actually did not even need to use the formula field.

Hello, I am trying to do the same but can't get it to work.
For Record ID I selected the ID "Attachment" (= name of the column my attachment are) and left the Fields one empty. If I do this I get an error message. See screenshot 🙂
Thanks to everyone wo can help