Warning on attachment size limit - Perfromance Goals

Summary:

Can a warning be set when a user tries to attach a file to large on a performance goals? We would like the issue to be addressed sooner than later in the process.

Content (required):

Currently users are trying to acknowledge performance goals and receive an error due to a attachment added 6 months ago to their goals that exceeds Oracle set limits. How do we have the system flag the attachment at the time it is being uploaded?

Version (include the version you are using, if applicable):

21D

Code Snippet (add any code snippets that support your topic, if applicable):