Sorry for all of the questions, but this stuff is all new to me, and a lot for my brain to process?! 
To be clear…
Let’s say I create a “Star Sprite” and decide to re-tool my Inbox to use the Star versus my Red Flag.
Right now the column my Red Flag is in is maybe 10 pixels wide.
So if I created a rectangular Sprite like this…
[---- THIS IS WHERE MY DIFFERENT STARS WOULD GO ----]
…then I could still use it in my 10 pixel wide column, right?
(In other words, the Sprite can be very wide, but as long as an individual Icon on the Sprite matches the width of the available space you have, then you are okay, right?)
So does that torpedo my use of a Sprite?
I mean the whole point is that I want a clickable, actionable Star Icon which by design would NOT have Text inside of it?!
(If I wanted Text, then I’d just create a Form Button that said “Mark as Important” and be done with it?!)
Oh, I see this is a deeper topic than I first thought! 
I guess you would lean towards that approach versus the Sprite, right?
From a visual standpoint, this seems to be the key difference…
If I used a Sprite, I could create the first Star with a Light Gray Outline, and then a second Star with a Darker Gray Outline, and then a third Star which is Yellow.
If I used the “Miter Approach” - not sure what you call it?! - then I could create the first Star as Solid Light Gray, the second as Solid Darker Gray, and the third as Yellow.
Sound right?
Cool!
Is that like a Gilder-Levin thingy?? :-/
And does that mean that Sprites are poor choices for Accessibility, or is the technique you are referring to a sufficient workaround?
I thought we agreed you would delete everyone else’s PM’s so there was room for my “love letters”?? 
Sincerely,
Debbie