Why does IE7 specify a mime-type of image/pjpeg rather than just image/jpeg?

Question

When uploading a file (jpeg) via a form in IE7 I am seeing a mime-type of \"image/pjpeg\" instead of \"image/jpeg\" (as I see in Firefox or similar). It\'s easy enough to work

Answer 1

I believe it's because the JPEG you're working with is a progressive JPEG, which has a different mime-type.