Hi Christian! Here's a tip: when uploading an image to replace one of inferior quality, you can upload over the existing image by navigating to the file page and clicking the "Upload a new version of this file" link. That way, it saves the history of the image on the wiki, which can be helpful in the future. If you have questions, feel free to let me know.
Heya, thought you might to know we have File:Bear-MisterRogers.jpg over on Mister Rogers' Neighborhood. It's not the best screenshot, and I had to edit out a logo, so if you've got better quality source, feel free to "Upload a new version of this file" if you'd like.