There are a number of reasons you may want to search for a duplicate picture on the Web even if you already have an image file in your possession. Perhaps you hope to find information to help you identify an image. You may want to look for a revised or higher-definition copy. You could just be curious about other sites that are displaying the same picture. Whatever your motivation, there are powerful reverse image search tools you can use to find duplicate pictures on the Internet.
Reverse Image Searching
A search for a duplicate picture, such as a photograph, drawing or painting, is known as a reverse image search, and uses the image itself, rather than a text description, as the search input. A reverse image search creates a "fingerprint" of your original image based on distinct features of the picture, such as prominent lines, points, edges, colors and textures. It then searches its own index of stored images to try to find a matching image.
A reverse image search only looks for duplicate images. For example, if you have a photograph of a well-known celebrity, a reverse image search will only locate duplicates of that photo, but will not find other pictures of the same celebrity. However, if the photo has been modified slightly, such as a text overlay or a change from a rectangular to a square format, the reverse image search will still recognize the image fingerprint and will display the modified photograph in its results.
Search Duplicates With TinEye
TinEye is one of the Internet's earliest reverse image search engines. Use any one of three methods to search for duplicate images at TinEye: Upload an image file from your computer, enter an image URL in the search field or drag and drop a picture from the Internet anywhere on the TinEye page. You can also download a browser extension from the site that lets you right-click an image for rapid searching. TinEye then searches its index of billions of image files to see if there is an image with a matching fingerprint.
Other Reverse Image Search Tools
Google Images also offers a reverse image search function. Google Images functions similarly to TinEye in terms of image input and browser extensions. Search results at Google Images, in addition to displaying duplicate images, also display images that are similar to your original picture, based on overall matching of colors and composition. For example, a search on an image of twins wearing red is likely to return similar pictures of other siblings in red outfits.
Newer reverse image search tools are available as well, including those from Bing and Image Raider. Since different search engines access different image libraries, a search at one site will sometimes uncover a duplicate image that was not available at another site.
Uses of Reverse Image Searching
Reverse image searching is an important tool for protecting your intellectual property. Use duplicate searching to find other sites that are using your photographs, drawings, artwork or other image files. If the sites are using your images without your permission, you can contact the site owner to request that your image be removed or that the owner take other steps, such as providing a credit and linkback for the image or paying you for its continued use.
Duplicate searching can help identify an unknown image or provide additional information about a picture. Other sites that carry the image you search for may include information such as the image title, author, creation date or subject matter. For example, searching on an unknown corporate logo can usually identify the company using the logo. You can also find better copies of an existing image, such as a duplicate at a higher resolution or with a format more suitable to your needs.
Don't Forget Text Searching
Reverse image searches may not always find a duplicate of your original image, but that is no assurance that such a duplicate does not exist somewhere on the Internet. If your initial search turns up no results, try a text-based search at a site like Google Images or Bing Images. Use search terms to describe your picture and scan the image results for duplicates.