Is there a size limit to items that are uploaded in a survey/form?

I am testing your service to see if it will work with what my company needs and encountered a problem in testing it out. When I opened the survey with my iPhone and attempted to attach a photo, it said the file could not exceed 1024kb. Is this becuase I'm testing this with the free version or is that the actual file size limit? What is the limit?

Thanks,

Christina