Photographs in JotForm - Underscore reading as %20 instead of _

People have inputted photographs into our form. We asked them to name them "lastname_firstname"  Some are coming in as "lastname%20firstname".  Is this an issue between different platforms e.g. using a cell phone instead of a PC or using a MacBook instead of a PC?  What could be causing this?

The "space" character is equivalent to "%20" in ASCII URL encoding. It means that your user is using "space" instead of "_" on the file name.

Here's an example:
lastname firstname = lastname%firstname

Please advise your users to make sure they use underscore and not spaces.

Let us know if you have any questions. Thank you.