Add image to checkbox value attribute in html email response

I've created a website postcard form using Coffee Cup Form Buider (yes, I posted this question on their forms) https://www.clevelandofficeleasing.com There are (4) checkboxes with (4) thumbnail images to the right of them. What I need to happen is that when a visitor chooses a city checkbox, the confirmation email they receive will not only include the "value" attribute of the checkbox but a larger version of the image that resides on the web server. Example for the "Cleveland OH" checkbox: https://clevelandofficeleasing.com/img/cleveland.jpg. I just can seem to figure out how to code it properly. I have not included any code snippet since the Coffee Cup software generates the form responses, this is more of just a general "How would you manually code this?" question. Thanks, -Ron