File with JPG extension acts like a GIF with a cat shooting a gun with heavy kickback

Question

I recently came across this image which seems like a normal GIF:

seems a gif image

Even imgur stores it as a GIF when I uploaded it here.

But when I saw the link, it was a JPEG image, unlike a GIF than what I had expected!

Here's the link: https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash3/559307_325955130827518_630404691_n.jpg

It's a GIF with the wrong extension. The first 6 bytes of the image are GIF89a, which is the [magic number](http://en.wikipedia.org/wiki/Graphics_Interchange_Format) for a GIF file. — vcsjones, Jul 17 '12 at 19:58
What makes it on topic other than filling in the question box? — random, Jul 17 '12 at 20:05
Finally, a canonical question on this topic with a title I can actually *remember.* — Shog9, Jul 17 '12 at 20:07

score 21 · Accepted Answer · edited Jul 17 '12 at 20:36

21

This is actually a .gif - look at the headers of the HTTP response.

The MIME type is image/gif

So it doesn't matter what the URL says at the end - it's the MIME type that determines how your browser interprets it.

A lot of sites use this (I guess to throw off harvesters?) imgur.com often reports the wrong extension, for example. Try going to i.imgur.com/yourpic.txt - it should still show up as a proper gif.

edited Jul 17 '12 at 20:36

Robert Harvey

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answered Jul 17 '12 at 19:58

Erty Seidohl

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Hmm... If you're using chrome, hit f12. Then go to the "Network" tab and look for your image. Click on it, and check out the "headers" tab that appears. Not sure for other browsers, sorry. – Erty Seidohl Jul 17 '12 at 20:05
@gopi1410 use the chrome dev tools if you have chrome. Ctrl Shift I should bring it up. Refresh the page to catch types – Ben Brocka Jul 17 '12 at 20:05
C-S-i also works for Opera (Dragonfly) – sehe Jul 18 '12 at 00:07

File with JPG extension acts like a GIF with a cat shooting a gun with heavy kickback

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