Delete a photo submission

Is there a way to "Delete" a file once added to a form, specifically on iPhone?

I tried on the web form, and it seems if you click on Upload again, and then simply "Cancel" the photo deletes, same on Android, but on iPhone if you cancel the original file remains. Is there a way to add an X or a remove file button so this is consistent across platforms?

With "Allow multiple" enabled, there should be an option to remove files added to the form before completing the submission. 

This can be found in the options menu for your upload field.

If that does not work, it may be a limitation on the browser.  Try using Chrome or FireFox on the iPhone to see if those browsers include the option to remove already uploaded files.