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I thought this question might get a better response in AskUbuntu, as it seems to have more to do with Ubuntu than Windows at a glance.

Let's say I have a foo.mkv file. Thumbnail previews work in both Windows 7 and Ubuntu.

When I change the filename to anything random like or when I remove the extension itself (making it just foo), Nautilus shows thumbnails normally like if it can recognize what type of files they are - without looking at file extension.

This however, doesn't happen in Windows 7. Windows starts asking me things like which application I want to use to open that file as soon as I remove file extension (forget thumbnails...) etc.

So, How does this thumbnail preview work in Windows 7 and Ubuntu? What makes Ubuntu recognize files "out of the box" unlike Windows 7?

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don't forget to upvote the question and the answer that pleases you more! ;) – Bruno Pereira Jun 16 '12 at 19:49
haha indeed... A great advice from an experienced member... ;) :P – Forbidden Overseer Jun 16 '12 at 20:02
I don't think linked question is exact duplicate, but it partially answer the question. So don't put close votes blindly :) – Tachyons Dec 26 '12 at 12:26
@Tachyons: hmm... but isn't the left out part about Windows 7, which means this question is part duplicate and part off-topic? Even then I admit that I put that close vote a little too fast, without thinking. – Forbidden Overseer Dec 26 '12 at 12:30
No windows7 part is not offtopic, because it is for comparison only, AFAIK Your question is How the thumbnail is generated in ubuntu and how it is differes from windows7, It is not answered yet. But the question why ubuntu correctly shows thumbnail even when extension is wrong is answered by the linked question. I hope you got my point :) – Tachyons Dec 26 '12 at 12:37
up vote 1 down vote accepted

I think Ubuntu uses the file header to identify file type and generate the thumbnail on that basis , but in windows a file containing meta data named Thumbnail.db would be updated when windows explorer scan file types (based on the file extension).

This document supports my answer .

Ubuntu uses Nautilus that complies with Freedesktop implementation, that uses file MIMEtype . Visit above link for more specifications.

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That seems like what might be happening in case of Ubuntu like you said, but it would be much more clear if we can confirm it - say some part of ubuntu which does this job. I couldn't find something like that (which might be used by Ubuntu) in my search. I would be happy if you can point out something like "magic", which does this job in nautilus. – Forbidden Overseer Dec 28 '12 at 19:28

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