If you upload your own photo to Google Classroom it darkens. No one likes this. It is not your imagination, you are not doing something wrong.
THERE IS NOTHING YOU CAN DO ABOUT THIS!
Apparently it has something to do with the rules for material design. What I really want is to choose my own accent color that goes with my class. After I upload the image I would like to be presented with a palette of colors to choose from. I feel confident all of us would like this. Please send feedback and send it often 🙂@GoogleForEdu my #googleClassroom banner dims. Please let me customize the theme of my classroom by choosing my theme color and not making the header darker.