If we upload a file that's within the limits of the configuration settings then the files array contains
data about the uploaded file including the size in bytes so we can also use this to restrict the size
of uploads in individual farms.
Let's restrict the size of article images to one megabyte.
So when the form is submitted if the size of the uploaded file is greater than 1 megabyte in bytes we'll
throw an exception.
Note I've put 1 million bytes exactly for one megabyte.
If you want to get in to whether one megabyte is exactly a million are one of these other two values.
There's a question here that goes into that in much more detail.
We'll keep it simple and put one million.
So if I try and upload a file that's less than the server limit but greater than 1 megabytes.
Then we get the error message coming from the exception.
We just added.
I picked a one megabyte limit as it's a nice round number but obviously if you want to be able to upload
larger images than this then all you need to do is change this limit.