Preserved Topic: HTML Prob

Hey, a friend of mine saw this on the telly the other day: it was a quiz on tv with a handsome prize to boot. The question goes: Is it possible to display a graphic on a web page and prevent the user from d/loading it to his hard drive?

I think its impossible. What say u?

I was thinking of blocking the right-click menu (Windows) but the user can always save the page. Is there any way to prevent the user from d/loading the image?

Seems to me like it would be impossible. If nothing else the user can always make a screen dump and paste the image in a graphic program. But then I guess that is not really "downloading" strictly speaking...
If someone block the right click you can just check the source and see exactly where the image is and then go do it directly.
And also, once the picture is loaded in the browser is it also saved in the cache on the hard-drive, isn't it?

yeah, absolutely right... so i guess its not really possible after all

Wonder if there is a catch to this somewhere... like maybe displaying the image like a streaming video or something which cant be directly d/loaded

Well, although its technically not downloading, anyone with a decent graphics program can always just hit Print Screen and save the image that way. No way to prevent against that.

I would say if you embedded the image in something like Flash it would prevent it.

I've seen some java applets that display images that don't allow download....I saw one once that returned an alternate image when someone tried to download the desired image

Yes it's possible.

No, it's not possible.

I mentioned an interesting technique that won't stop determined image thieves, but will confuse many. Make yourself up a new suffix for image files, instead of .GIF, maybe I could start ending all of my files .DOC, or better yet .TXT. If you call this mis-named image inside an <img src> tag it will display normally, but if you try and download it it will get a garbled up file. Here, it doesn't always work, but try with this one...

Bear in mind though, I know that I could grab any image I wanted, regardless of the protections offered.

Your pal, -doc-

Doc, that's a very nifty idea but I just tried it on my pc and it downloaded it as a gif file and it looked just fine. However, I can see how this would definitely not work on other browser/platform configs. I was thinking another way to confuse would be to put a blank.gif on a div and position the div right over another image. That should confuse some folks.

As to the original question... not possible.

The same thing here, my IE5.5 recognized it as gif and saved correctly...

saved it correctly.. doc..

Apparently, O5 doesn't look at the inage file data. It downloaded as a txt file and when I opened it, there was gibberish. However, I renamed it .gif and it opened as the proper image. So, you're right, Doc, it would serve to confuse the uninitiated. Just a speed bump though

Yeah IE 5.5 got it good...

Yah, the biggest problem is that I can't think of a method that would foil *me*, so how can I hope it will stop others? I trust to my friends on the net to let me know if somebody is stealing my stuff, and then I hunt them down and c*****n them but good! (Ditto with the help of my friends!) This doesn't just work for me, we have to track down one of Allgood's admirers every month or so, and our record has been near 100%.

Your pal, -doc-

The file extension thingie was coool. Hey at least now i know there *is* some way whatsoever But isnt there any good way we could put up an image and not have the user d'load it? Boudga, how do you do it using a Java applet? Is the Flash method foolproof?

Well, when you have an applet or a flash file....there is no image file there....it's an applet or a flash file. However, the user could still make a screenshot of the page and crop the image out of it (possibly loose some quality, but still do-able.

In order for the browser to display an image, it must download the image. That's just the way it works...so even if you do all the fancy crap to stop people...the image is still sitting on their hard drive in temp/cache folder.

DL-44's right, if they can see the image, they've already downloaded it. And even if there's a bunch of stuff worked into the page to keep them from saving it to their hard drive, if they're determined, they can write their *own* web browser that will download the image and let them save it. So, I'd say it's not possible. (Heck, they could take a picture of their monitor if they were desperate.)

Thanx a lot guyz What I dont get is, if an img is displayed as an applet, what format does the browser cache it as? If it does cache it, will it be an image file?

I've visited sites advetrtising secure image encryption. It requires a plugin to view them, but you can NOT take a screen grab. It's freaky.

However - you need to be SO paranoid about security that you are willing to require visitors to download a plugin to see your stuff. There are ways to totally encrypt an image, but not ways I personally consider practical or effective.

Slime has the ultimate work-around - photograph the screen


[This message has been edited by Steve (edited 03-27-2001).]

Actually, steve, there's a way around that as well. Basically, if you want someone to see an image, then they can also copy it in some way or another. Doc's right, I can't think of anything that would stop me if i really wanted to get an image so I don't know how I could stop someone else.

In fact, here's the only foolproof way of stopping someone taking an image. Here, take this image I dare ya':

Even supposing that hardware had built-in encryption so that the image stayed encrypted all the way to the video card, someone would no-doubt develop a pirating dongle that could intercept the image. As much as I hate image pirates, I hate the idea of full-time encryption even more. You know Microsoft has a plan to do this for music where companies sign up their content with MS, sound card manufacturers build decryption into their cards to MS specs, and Microsoft gets monopoly power over the only foolproof media protection method.

Nothing gets around print screen, but I suppose you could construct your pictures entirely of 1x1 tables with background colors. That would be rather large, though.