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.
If it's before the form is submitted, you can use our Image Upload Preview widget: http://widgets.jotform.com/widget/image_upload_preview. Here's how you can add a widget to your form:
Image preview is available in the form submissions page: http://www.jotform.com/help/269-How-to-view-Submissions. You can also create a Grid Report and enable modal window: