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I store the files for my website offline in a local folder under My Documents. Every time I look at one of my HTML files in the preview pane, Windows Explorer notifies me that it has blocked the pictures to keep the sender from identifying my computer. What sender? These are my own files, which were created offline, and later uploaded to my site. Also, my computer is not even online to the internet when this happens. It's infuriating! How can I indicate to Windows that these files are neither online nor downloaded??

BTW, I've seen this question asked a number of times before, but it's always misunderstood and never answered correctly. I'm not talking about the browser, this is about Windows Explorer, and not all of my pictures are being blocked, only the ones that are embedded in HTML files.

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One of the ways that people try to check to see if someone has received an e-mail is by embedding a 1 pixel image in the message. When the message gets read, if the picture is rendered, the server that hosts the 1 px image (the sender) knows about it. That is what they are trying to protect you from.

The only way I've seen how to do this is something like harrymc's answer to this question).

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  • This presumably wouldn't apply to an image referenced locally (as opposed to an external URL) as in OP. Feb 15, 2016 at 18:45
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I agree with @soandos answer above (and it is helpful), but another reason to block images is that they can contain information that causes your image decoder to go wacky and allow some kind of remote code execution exploit. While this is rarer these days (we casually view images in our web browsers all the time, don't we?) it's still possible in theory. Combine that with the fact that Windows Explorer runs with more privileges and more trust than an Internet Explorer browser (IE runs in a "sandbox" with very limited privileges, usually) and you've got the makings of an attack vector.

When you say "embedded in HTML files", what do you mean? I'm not sure what "embedded" actually means in this case. Is the actual data of the image within the HTML file somehow? Or is it just a standard link to an image, a la the img tag?

I've only seen one standards-compliant way to embed actual image data within an HTML file; and that's the Data URI scheme -- but I'd be surprised if you're using that rather than the img tag, which is strictly speaking not embedding, because it's an instruction for your web browser to go out on the internet (or wherever) and download the resource.

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  • Or MHTML, MAFF, Webarchive, etc.. But yea, the distinction between embedded and linked (<img>) is important. Also potentially important is whether linked images are stored locally or on an external server, but since @Gerry says he's not connected to the internet, it does rule out external server.
    – Bob
    Jul 12, 2012 at 5:04

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