One pixel is worth three thousand words

> Headers can contain all sorts of meta-information about an image.

We accept logo images for one of our products that I work on. At one point, our system was failing because the images being uploaded were too big, so the client sent us the image they were trying to upload and we started looking.

Imagine my surprise when I started digging through the file only to find a bunch of XML... which contained binary data... which contained the original, un-resized image that the logo was created from.

Turns out that the piece of software the client used to resize their image to a smaller size, suitable for a logo upload, had an option to preserve the original file inside. Along with a bunch of other information, such as the author, date, history...