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.
Yes, this could be because your form needs to upload all the uploaded files, it also depends on the size of the image, if it is a large image and it are multiple images this will be noticed when submitting the form, you can limit the size of the files that are uploaded, take a look on this guide to do it: http://www.jotform.com/help/33-Changing-the-Upload-Size-Limit.
If you are referring to images that you are showing in your form, then it does not affect the form because these images are loaded as soon as the form is loaded and they are not uploaded when the form is submitted.