You may have thought transparent images on Muppet Wiki are rare. Yet, you find white backgrounds.
However, Muppet Wiki has many transparent images, and to prove it, here is a catalog.
Note that only .png, .gif, and .svg images can be transparent; yet, not all .png, .gif, and .svg images are transparent. Also, not every transparent image is here. I'll be adding more and more images here. If you see a transparent image, write to me on my talk page!