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Protecting Your Images
Don't want people stealing your images off your site?
Well here is a solution I implemented for a client, that makes the
only way to grab your image is thru a screen grab (see example here).Now this is not an absolute solution to the problem since there isn't
one, but this is best way I've been able to implement todate, withoutadding watermarks to the images.There are two parts to this implementation.
First you require a cgi script (see image.pl below) that: 1/ checks to
see if it's your page calling the image (using HTTP_REFERER) as yousee I'll allow any page from the /test/directory to qualify. If youuse another CGI ensure you explicity disallow it from qualifying. 2/pipes your protected image from a safe directory 3/ ensures that thebrowser won't cache the image file by setting both the PRAGMA andEXPIRES headers. (even try viewing using page info)Next part to the solution is to use javascript (see code in html
example below) in your page to ensure the user can't use the imagesave feature by: 1/ loading a dumby image which appears when ever themouse is over the image, thereby disabling the right mouse, save imageas. 2/ using javascript to load the desired image, then swapping itwith the dumby once loaded and whenever the mouse is NOT over theimage.Now also remember that your dumby image size has to be the same as the
image you want to display, now this wasn't a problem for me since Iensured all of my clients photgraphs were the same size.==== image.pl ===========#!/perlrequire "Cgi-lib.pl";&ReadParse(*search);if ($ENV{'HTTP_REFERER'} =~ m#http://www.ematchcorp.com/test/# ) { $expires='Expires: Wed, 26 Feb 1997 08:21:57 GMT'; $pragma='Pragma: no-cache'; $tmpfile="c:\\inetpub\\www\\ematch\\images\\$search{'file'}"; open( FROM, "< $tmpfile" ); binmode FROM; binmode STDOUT;# Print out the contents of the image file. print "Content-type: image/$search{'type'}"; print $expires,""; print $pragma,""; print ""; while (<FROM>) {
print $_; } close FROM;} else { ## Unauthorized access print "Content-type: text/html";
print "<html><body>copyrighted material</body></html>";}exit;====== end image.pl======== ==== begin index2.html==========<html> <head> <title>image example</title> </head><script language='javascript'>function ImageLoad() { window.status="Image cache test"; iFake = new Image (); iFake.src = 'loader.gif'; iReal = new Image (); iReal.src = '/cgi/image.pl?type=jpeg&file=img0064.jpg'; document.images['slide'].src=iReal.src;}</script><body onload='ImageLoad();'><a href="" onMouseover="document.images['slide'].src=iFake.src;" onMouseout="document.images['slide'].src=iReal.src;"> <img src="loader.gif" name='slide' border=15> </a></body> </html>=========end index2.html ======
