We are on Nintex 2013 (Forms 18.104.22.168) and are using a multiple line of text field that is set up as Enhanced rich text (Rich text with pictures, tables, and hyperlinks). We are only using this field to have an image (screenshot) inserted into it. We have a validation rule set up, as when the form is signed this field becomes a required field. We are using isnullorempty() for the other similar fields on the form to validate that they are not blank, but with this multiple lines of text field, when we insert an image into it, it is still showing up as invalid with the isnullorempty() validation. I verified that typing a single character into this field gets it past the validation rule, but that isn't what we are looking for. How can I validate that it has an image inserted into it?