JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
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.
Change the upload file size in your form, this guide will help you to do it: http://www.jotform.com/help/33-Changing-the-Upload-Size-Limit.
Do note that this uses your upload space in your account, as you are using a free account you only have 100 MB, once you reach the limit you will receive a message and then you will need to delete your submissions in order to get free space or you may upgrade your account to get more space without the need to delete your submissions: https://www.jotform.com/pricing.