Uploaded user skins (and capes) are PNG images. The PNG format allows multiple compression methods as well as multiple color types.

However, you just accept these images as they are and send them to clients without removing the meta tags.

You could have faster loading skins/capes, save bandwidth and AWS costs by compressing images and removing meta tags before storing them.

For example, the current skin of user f71cca5d3638479490dbcde943574e9f has at least 1800% of file size than it needs to be. (54KB instead of 3KB at most)

And it's fairly easy to find out that the MINECON 2013 Cape was created on 2013/03/13-12:09:15 using Adobe Photoshop CC on a Macintosh. That information isn't worth being downloaded every time.

There are multiple existing tools to compress PNG images, e.g. ImageMagick, PNGOUT, AdvPNG, Pngcrush, OptiPNG, etc.

PS: It might be possible that some images (e.g. when created using a real-world photo) contain GPS tags, revealing the creator's location.