I have an uload field which is optional, it can be left empty. But when it is is used, I want to validate the size and content of the attachment. So I use this validation in the model:
validates_attachment :attachment, content_type: { content_type: ["image/jpeg", "image/gif", "image/png"] }, size: { in: 0..500.kilobytes }
This works when there is an attachment, but fails when it is left empty. How can I make sure it only validates when there is an attached file?
The solutions mentioned here are not working unfortunately.