Protecting Images: Five Methods Explored

With image theft such a large problem, artists and photographers have sought out methods to prevent plagiarism of their work. The cat and mouse game, which is almost as old as the graphic-capable Web browser, has escalated to encompass a wide variety of techniques from HTML tricks to image manipulation.

With so many means of protecting images, it’s worth taking time to step back and evaluate some of the more popular image protection methods and look at how they work, what their drawbacks are and how well they protect.

After all, the first step to achieving a goal is to figure out where we are and where we have to go. Only then can we start moving in the right direction.

The No Right Click Script

The oldest and, currently, most popular method of protecting image content is the use of a no right click Javascript. The code for this script is widely available in a variety of different formats and is easy to implement on just about any site. No advanded programming or HTML knowledge is required.

The script works by preventing people from using their right mouse button while on the site itself. This blocks people from simply right clicking on an image and saving the image to their hard drive.

The Drawbacks

The problems the NRC script creates are many and great. Many people, including myself, use the right click button to navigate around the Web. The right mouse button is also used to open Web pages in a new window or new tab if using Firefox.

Using this script can be very frustrating to legitimate site visitors who have grown used to the ease of use the right click menu provides. After all, the “Save Image As” option is just one item in a long list of the right click dialog and disabling it robs your site of a great deal of functionality to many of the Web’s most savvy users.

The Level of Protection

Perhaps the biggest problem with the NRC script is that is provides nearly no effective protection. The script is easily defeated by simply disabling javascript in the browser. Also, one can still drag and drop the image to their hard drive or simply save the entire page to their hard drive and pull it out that way.

In the end, the NRC script is nothing but a hassle offering no practical security. Though it might be useful in limited situations, such as image popup windows that are meant to be viewed and closed, it’s largely just a hassle and most Webmasters who use it would probably be better off with nothing at all.

Transparent Overlay

The transparent overlay, which was discussed previously, protects images by overlaying a completely transparent image on top of the image that is being protected. This way, when someone tries to right click on an image and save it, they actually save the transparent image even though they appear to be grabbing the one below it.

It’s a technique which can be applied a number of ways, including with HTML, CSS and advanced programming languages, and can be adapted to almost any kind of site.

The Drawbacks

Unlike the NRC script, a transparent overlay does not hassle the end user with limited access to the site. However, it requires a great deal more knowledge and time to execute than simply pasting a few lines of code into a page. Even though new techniques have simplified the process, it’s far from a matter of copy and paste.

Its complexity can make it somewhat tedious to apply over large sites and new Webmasters often find this a very intimidating thing to do. However, its no-hassle approach to protection still makes it preferrable to the NRC script for general use.

The Level of Protection

The overlay relies mainly on the habits of image thieves. Most image thieves simply go around, right click images they want and save them to their hard drive for later use. They don’t check what they save and, generally, don’t bookmark where they got them from. Thus, tricking someone into downloading a transparent image can be a very effective technique against your average thief.

Still, it is an easily defeated technique. Saving the entire page, taking a screenshot or looking through the HTML code to find the location of the hidden file can defeat this technique in very short order.

So, while it’s useful against the more passive thief, a determined one will still have no trouble lifting the original image. Still though, it’s much more effective than the NRC script, that much is for certain.

Segmented Images

Many times, what appears to be one image is really two or more. This works because HTML allows for images to be positioned directly next to one another seamlessly. With that in mind, many artists have taken to cutting up their images and then using HTML to piece them back together. To the viewer, the image is whole but anyone who tries to lift the image will quickly find out they have (quite literally) a puzzle on their hands.

This is because “saving” the image via the right click function will only save a portion of the image. If anyone wanted to steal the entire thing, they’d have to save all of the pieces and reassemble them on their own. Theoretically, anyone who’s good enough with image editing to pull off that feat is good enough to create their own content.

The Drawbacks

Once again, this method doesn’t hassle end users and some even claim it speeds up loading times. However, applying this technique is much more complicated than any other out there and requires a fair amount of both image editing and code manipulation. (Note: Free software is available to make this process easier) To make matters worse, differences in how browsers display code can create gaps between the segments of the image if its not exactly right.

Also, the technique isn’t very useful for smaller images. Only images which are large enough to be broken apart in several pieces really qualify for it. If your work happens to involve smaller pieces, such as icons, there’s not much good that this protection method can do for you.

The Level of Protection

Though this technique defeats right clickers, those who save the entire Web page and those who drag and drop, it doesn’t stop those who take screenshots or simply have the patience to piece together the different segments.

Though this technique certainly provides a greater level of protection, at the cost of greater effort expended, it won’t stop the most determined or creative thieves. However, plagiarists who have a low to moderate level of skill will probably be thwarted, or simply decide that the time commitment isn’t worth the reward.

Either way, you win.


The term “watermark” originally referred to a design imprinted on a piece of paper that was visible when held to light. However, on the Web, it refers to either a logo or line of text placed over an image to signify ownership. A watermark can be either solid or translucent, depending on the technique used, but is generally visible, to some degree, to the viewer.

Generally, watermarks include something that signify the site that the image came from, either a logo or an address, and can be placed anywhere on the image from dead in the center to one of the corners thereof. The application of a watermark can be done in any image editing software but can be greatly simplified (and made more consistent) through the use of batch processing software such as Webthumbs.

The Drawbacks

Applying a watermark is a very simple matter. With the right software, all of your images can be watermarked in a matter of seconds and then the watermarked images are simply placed like any other graphic file. No HTML or other trickery required.

However, watermarking requires mutilating your images. It means taking an image you feel is worthy of protection and dirtying it up with a logo, copyright information or some other identification. Viewers almost always prefer clean images to watermarked ones and, even if the watermark is in an out of the way portion of image, it can be a hassle for them to overlook.

As such, watermarking is generally seen as a pretty extreme measure where the image is of great value, either financially or emotionally. A good example of this would be selling prints or paintings online. It’s also a common technique used on adult Web sites where watermarks serve both as promotion and protection.

The Level of Protection

Watermarks are, perhaps, the only form of perfect protection. Since the mark is visible to the naked eye, even taking a screen capture will offer no recourse. Furthermore, a halfway decent watermark can not be removed, even with advanced image editing skills and software, it’s unlikely that even the owner of the image could undo the watermark and that makes keeping the unaltered originals safe an extremely important affair.

The only caveat this comes with is that the level of protection does vary somewhat based upon the size and location of the mark. While a large mark in the center of the piece is virtually impossible to remove, a small one in the corner can be cropped out with minimal loss to the work.

Even then though, cropping and editing are steps that your average plagiarist aren’t going to take. There’s little doubt that watermarking provides the best protection of any method, though with possibly the highest cost.


Steganography is basically a big word that means “to hide a message inside something else.” It’s a form of cryptography, or code, where the message is buried in something that doesn’t usually carry text, like an image file.

In regards to preventing image plagiarism, it refers to making undetectable changes to the image that, though invisible to the human eye, can be detected by software trained to look for the modifications. Thus, someone can embed an image with a copyright notice that includes all relevant information to the image and then someone else with the decoding software can read it, all without the image looking any different to the average viewer.

This form of protection is often times also called “invisible watermarking” or “digital watermarking” and is increasingly being used by government bodies to ensure the validity of ID photos.

The Drawbacks

On the surface it seems like the perfect method. It’s protection that can be easily applied to many images quickly, the files can be used just like any other image file on your site and has no negative impact on viewers.

However, very few companies are involved in this field and, though Digimarc will allow you to embed and view their watermarks for free, services that offer protection through this technique can be very expensive, up to several hundred dollars per month.

This immediately puts this very powerful tool out of the reach of your average Webmaster. Most Web sites, especially art and photography sites, are personal in nature and are started with either no budget or a minimal one. Most simply can not afford this kind of protection and it winds up only being available to those who are running sites either for profit or who have the money to invest in thousands in a free product.

The Level of Protection

Interestingly enough, digital watermarking doesn’t do anything to prevent plagiarism. It will not stop anyone who tries to save your image or reuse it on their site. Instead, what it does is make the image trackable. Where text has always been easily searched for on the Web, this adds the same functionality for images, making it very easy to find duplicate copies of a graphic file the same way you can find a poem or an article.

The technique is virtually impossible to defeat without mangling the picture beyond recognition. Even though it’s unlikely a thief would even know that such a watermark was embedded in the picture, one who did couldn’t defeat it by simply cropping out a portion or making small modifications. Most good digital watermarks, such as Digimarc’s, aren’t defeated that easily. In fact, the only way to remove the encoded message is to virtually destroy the image, making it useless to the plagiarist.

If you can get past the high cost and the notion that this technique does nothing to actually prevent plagiarism, then this is probably the best combination of effectiveness and usability out there right now.


In the end, the technique you use, if any, will depend upon a variety of factors including the value of the image, both financially and personally, the size of the file, the nature of the image and the role it plays on your site. You have to chose the technique that is right for you in the specific case it’s to be applied.

This may mean you wind up using a variety of techniques on one site or multiple methods on a single image to maximize protection. However, do it with this fact in mind: There is no perfect method of image protection. If it can be seen on a computer screen, it can be stolen.

Just like with text, image plagiarism is not preventable, but you do have the power to raise the walls up a little higher to keep a large number of thieves at bay. Even if you just stop casual plagiarists, you’ve stopped a large percentage of the thieves out there and gone a long way to slowing the rate of plagiarism.

In the end, slowing the rate is about all you can hope to do.

[tags]Plagiarism, Content Theft, Image Theft, Javascript, CSS, Digimarc, Watermarking, Image Protection[/tags]

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