Flickr Weirdness

Here’s a strange thing. The images from the previous post were uploaded to Flickr, so I figured I’d just link to those files, instead of uploading duplicates to my website. But, I noticed something odd. Apparently, some of the “medium” size images that Flickr provides have a larger file size than the original images. WTF? How can they shrink a file, but make it larger? I’ve done a spot check, and it doesn’t happen with all images. Why it would happen with any of them is a mystery to me.