What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
I was able to see the issue as well when I checked your form.
This is happening because the source URL of the image does not exist. It looks like you have not shared the pictures in your Dropbox account.
You must grant public access to the images in your Dropbox account so that the pictures will be available.
Let us know if you're still not able to resolve it.