Main Page Content
Protecting Your Images
Rated 0 (Add your rating)
Log in to add a comment
(6 comments so far)
Mike Ashton
User since: August 30, 1999
Last login: August 30, 1999
Articles written: 2
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, without adding 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 you see I'll allow any page from the /test/directory to qualify. If you use another CGI ensure you explicity disallow it from qualifying. 2/ pipes your protected image from a safe directory 3/ ensures that the browser won't cache the image file by setting both the PRAGMA and EXPIRES 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 image save feature by: 1/ loading a dumby image which appears when ever the mouse is over the image, thereby disabling the right mouse, save image as. 2/ using javascript to load the desired image, then swapping it with the dumby once loaded and whenever the mouse is NOT over the image.
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 I ensured all of my clients photgraphs were the same size.
==== image.pl ===========
#!/perl
require "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\n';
$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'}\n";
print $expires,"\n";
print $pragma,"\n"; print "\n";
while (<FROM>) {
print $_;
}
close FROM;
} else {
## Unauthorized access
print "Content-type: text/html\n\n";
print "<html><body>copyrighted material</body></html>\n";
}
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> 