Aha! I see what you mean now. Today the colors are somewhat arbitrary but consistent, meaning there is not necessarily any meaning to the fact that constituents with the initials "SA" have a green background for their placeholder image, but it is true that all constituents with the initials "SA" will have the same green background. So the way it was built is intended to serve simply as a placeholder for Constituents that don't have a profile image and is intended to be consistent from Constituent to Constituent (assuming those Constituents have the same initials).

So, I'm afraid this suggestion isn't really in line with the way the feature was built. As such, I'm going to mark the idea as "Will not implement", but would still recommend using a particular profile image OR using a Constituent Attribute to help you discern "priority" at a glance on the Constituent list. I hope this helps!

Appreciate the suggestion, Jarod! Our thought as an organization was that as we prioritize people within our portfolios based on likelihood of next gift closing within the next 12 months, stewardship only status, etc. we could quickly identify them by the color on the initials when we are going through tags and adding/managing actions.  Green might mean a prospect who we expect will make a gift in the next 12 months, blue could be someone we just met, yellow could be our prospect pool we've yet to setup a meeting with, etc.  The goal would be total customization by organization, not that the colors at one org would mean the same thing at another. The color appears on the constituents initials but the initials have nothing to do with the prioritization. 

There are other ways at getting to these categorizations, the colors just seemed like a potential useful and quick way to visually represent the idea. 

Do you mind clarifying this idea? I understand that you want to be able to control what color is displayed for a particular pair of Constituent initials, but I'm failing to understand how that helps with portfolio prioritization... Is priority defined at your organization by the prospects initials?

Also, a quick suggestion:
You could always upload images to replace the initials. You could have an image that you upload to high priority prospects if you'd like and that might give you the "at a glance" priority that you are looking for.