as Xavier Perseguers noticed, color-blind people could find hard to understand which user is an administrator and which is not, because the icons superimposed on the photo differs only by the "shirt" color. See attached screenshot.
Suggestion
Suggestion for admin icon, "inspired" by some sites and an IRC client: put a crown on the head or use only a crown. (Just make sure that colour is not the only difference between two icons)
as Xavier Perseguers noticed, color-blind people could find hard to understand which user is an administrator and which is not, because the icons superimposed on the photo differs only by the "shirt" color. See attached screenshot.
Suggestion