"File is too big" -- but it's actually not..

[matheso]

I altered a php file the other day so now it says Maximum allowed file size is 30.00 MiB.

Yet when I try to upload a file that's only 5 mb, it says File is too big. I've attached a screenshot.

Obviously I only edited the title, and not the actual allowance. Which file should I be editing and where??

Thank you

[matheso]

Screenshot:

[matheso]

I changed the setting under the configuration tab and it works now.