(http://www.geocities.com/snail_5/AuthDigIm/)
Most of us have posted at least one photo of ourselves on the Internet, or circulated pictures through email, or downloaded an image to use for a project; all of these uses of digital images have associated problems of authenticity. What might happen to that picture of me? Whose cat is in this funny photo? Who should I cite if I want to reference this graphic? Issues of authenticity become especially important for photographers or artists who want to control the distribution of their work, and the Internet is a notoriously difficult place to police.
Issues this website will discuss include the basics of how digital images are stored on your computer and how they can be altered by other people, as well as methods for controlling what others can do to your images on the Web and how to get around anti-download techniques.
A digital image is any image that exists in the form of binary code (ones and zeros). Digital images can be created from analog images (by scanning photographs, drawings, prints, etc.) or can be created directly on a computer or other device (using drawing programs like Paint or Photoshop, or digital still or video cameras). Digital images can only be viewed on computer or television monitors; once an image is printed on paper, it isn't digital anymore.
Digital images are stored using the same kind of code that other digital information uses, a series of ones and zeros. Depending on the color depth of an image (how many different colors it has), it can take from one to thirty-two different ones or zeros (1 to 32 bits) to store the information for one pixel . For example, a black-and-white image only requires 1 bit of memory per pixel in the image; each pixel is colored either black (0) or white (1). A greyscale image (with varying shades of grey as well as black and white, also known as a monochrome image) requires 8 bits of memory per pixel, because each pixel can be one of 256 different shades between black and white (all of the binary-code numbers between 00000000 and 11111111).
You (or anyone else with access to the image) can change an image from color to greyscale, or color to black-and-white, but you can't go from black-and-white to greyscale or color, because the computer only keeps as much information as it needs (1 bit worth of information can't be turned into 8 bits' worth; it's easy to get rid of information, but hard to get it back, and impossible to pull out of nowhere). The same principle applies to things like resizing, recoloring, and some methods of compression.
For more information about digital images, especially as they relate to photography, go to Digital Image Basics by Jonathan Sachs.
Any publicly available digital image on the World Wide Web can be viewed, downloaded, edited, and disseminated, even if you don't want it to be. In fact, sometimes your images, or images of you, can end up on the web without you putting them there. If you email friends and family a picture of your baby, they can save it to their computer and do whatever they want with it, including putting it on their websites or forwarding it to other people. And if you are at a party, and someone takes a picture of you with a digital camera, they can post it to their MySpace or Facebook page, where anyone can view it. While laws about copyright and image use still apply, they are often almost impossible to enforce.
Imagine you are a digital artist, and you create a beautiful picture of a woman and put it on your website. A few weeks later, while searching for something similar, you see your image on someone else's site. It's smaller, and blurrier; it's named something completely different, and nowhere does the site say who created the image. It even has a different background than the one you had made. This image isn't exactly the same as the one you created—but it isn't much different, either. Is this image still “yours”, despite the alterations? Is this image “authentic”?
Or imagine you are looking for a picture of a cat to use on your pet store's business card. You search Google Images for “cat” and find millions of pictures, but you can't find out who the one you like belongs to. The same image appears on different websites in different sizes and filetypes, and it's totally unclear which of them actually created it. How can you ask permission to use it if the image has been disseminated so widely that the original version is buried in among thousands of others, many identical? These are just a few of the issues that affect our daily use of digital images.
Walter Benjamin, in The Work of Art in the Age of Mechanical Reproduction, says, “ Even the most perfect reproduction of a work of art is lacking in one element: its presence in time and space, its unique existence at the place where it happens to be.” This became the basis of discussions of the authenticity of images. However, when applied to digital images, it becomes much, much more complicated, as they have no physical location. Is the only authentic version of a piece of digital artwork the one on the author's hard drive? Is the only authentic version of a digital photograph the one in the photographer's camera?
Digital images can be resized, compressed, uncompressed, composited, recolored, distorted, filtered, and edited in any number of other ways, many of which are invisible unless their code is compared to the code of the “original.” If the changes are not visible, does that make the image any less authentic?
While we can only conclude that authenticity does not seem to be an absolute ideal, image creators or copyright owners can attempt to maintain the relative authenticity of their images, by preventing other people from editing their images or displaying them without the appropriate credit. And of course, there are also ways to circumvent such methods of control. All of the control methods, however, require medium to strong familiarity with how websites are created.
The most common way that people take images from the web and download them to their computers is to right-click the image and choose “Save As” from the menu. The easiest way to discourage this is to add a small piece of JavaScript when creating your website. Simply copy and paste the following code after your <HEAD> tag:
<SCRIPT LANGUAGE="JavaScript1.1">
<!-- Begin
function right(e) {
if (navigator.appName == 'Netscape' &&
(e.which == 3 || e.which == 2))
return false;
else if (navigator.appName == 'Microsoft Internet Explorer' &&
(event.button == 2 || event.button == 3)) {
alert("Sorry, you do not have permission to right click.");
return false;
}
return true;
}document.onmousedown=right;
document.onmouseup=right;
if (document.layers) window.captureEvents(Event.MOUSEDOWN);
if (document.layers) window.captureEvents(Event.MOUSEUP);
window.onmousedown=right;
window.onmouseup=right;
// End -->
</script>
Other methods of discouraging downloading, which usually require special software or advanced coding skills, include creating decoy images (i.e., when you right-click and choose “Save As,” the image that you save is different than the one you thought you were getting. This is the method used by Flickr), turning the images into Flash objects, or adding a watermark to the image (so that people can still download your images, but your name or website remains visible).
The easiest way to get around these techniques is simply to use the Print Screen function; make sure the whole image is visible on your monitor, then press Shift + Print Screen. Open Paint or a similar drawing program and choose Paste, then save it to your computer. This method will work no matter what as long as you don't need an exceptionally high-quality version of the image. Watermarks can be removed (effectively) by editing them in Photoshop, usually using the Clone tool. This is a little more difficult.
Naturally, you should only be using these workarounds if you intend to follow the guidelines for fair use of copyrighted material, and you should only use copy prevention methods (aka digital rights management systems) if they allow for fair use.
Authenticity is tied to value, and most of the time you don't need to worry about how valuable an image is except for as it relates to what you are searching for. Is it a picture of a kitty? Right, I'm good to go. Is it a picture of my ex-boyfriend? Yes. A little too high-contrast, but that's okay. Is it going to get way too many strangers to talk to me if I put it on my MySpace? Absolutely.
But sometimes issues of authenticity, especially as they relate to artwork or “Quality,” become part of what you need to look at to use an image, or to analyze it, or just to know the image. Find out what issues matter to you, and which are irrelevant, and conduct your investigation based on that.
by Danyn Oakes, 2008