With image search, just as with web search, Google's goal is to provide the best and most relevant search results to our users. Following the best practices listed below (as well as our usual Webmaster Guidelines) will increase the likelihood that your images will be returned in those search results.
Don't embed important text inside images
Avoid embedding important text in images for elements like page headings and menu items because not all users can access them. To ensure maximum accessibility of your important text based content, keep it in regular HTML.
Tell us as much as you can about the image
Give your images detailed, informative filenames
The filename can give Google clues about the subject matter of the image. Try to make your filename a good description of the subject matter of the image. For example, my-new-black-kitten.jpg is a lot more informative than IMG00023.JPG. Descriptive filenames can also be useful to users: If we're unable to find suitable text in the page on which we found the image, we'll use the filename as the image's snippet in our search results.
Create great alt text
alt attribute is used to describe the contents of an image file. It's important for several reasons:
- It provides Google with useful information about the subject matter of the image. We use this information to help determine the best image to return for a user's query.
- Many people-for example, users with visual impairments, or people using screen readers or who have low-bandwidth connections—may not be able to see images on web pages. Descriptive alt text provides these users with important information.
Not so good:
<img src="puppy.jpg" alt=""/>
<img src="puppy.jpg" alt="puppy"/>
<img src="puppy.jpg" alt="Dalmatian puppy playing fetch">
To be avoided
<img src="puppy.jpg" alt="puppy dog baby dog pup pups puppies doggies pups litter puppies dog retriever labrador wolfhound setter pointer puppy jack russell terrier puppies dog food cheap dogfood puppy food"/>
alt attributes with keywords ("keyword stuffing") results in a negative user experience, and may cause your site to be perceived as spam. Instead, focus on creating useful, information-rich content that uses keywords appropriately and in context. We recommend testing your content by using a text-only browser such as Lynx.
External anchor text (the text pages use to link to your site) reflects how other people view your pages. While typically webmasters can't control how other sites link to theirs, you can make sure that anchor text you use within your own site is useful, descriptive, and relevant. This improves the user experience and helps the user understand the link's destination. For example, you might link to a page of vacation photos like this: Photos of our June 2008 trip to Ireland.
Provide good context for your image
The page the image is on, and the content around the image (including any captions or image titles), provide search engines with important information about the subject matter of your image. For example, if you have a picture of a polar bear on a page about home-grown tomatoes, you'll be sending a confused message to the search engines about the subject matter of polarbear.jpg.
Wherever possible, it's a good idea to make sure that images are placed near the relevant text. In addition, we recommend providing good, descriptive titles and captions for your images.
Think about the best ways to protect your images
Because images are often copied by users, Google often finds multiple copies of the same image online. We use many different signals to identify the original source of the image, and you can help by providing us with as much information as you can. In addition, the information you give about an image tells us about its content and subject matter.
Webmasters are often concerned about the unauthorized use of their images. If you prevent users from using your images on their site, or linking to your images, you'll prevent people from using your bandwidth, but you are also limiting the potential audience for your images and reducing their discoverability by search engines.
One solution is to allow other people to use your images, but require attribution and a link back to your own site. There are several ways you can do this. For example, you can:
- Make your images available under a license that requires attribution, such as a Creative Commons license that requires attribution.
- Provide a HTML snippet that other people can use to embed your image on their page while providing attribution. This snippet can include both the link to the image and a link to the source page on your site.
Similarly, some people add copyright text, watermarks, or other information to their images. This kind of information won't impact your image's performance in search results, and does help photographers claim credit for their work and deter unknown usage. However, if a feature such as watermarking reduces the user-perceived quality of your image or your image's thumbnail, users may click it less often in search results.
If you don't want search engines to crawl your images, we recommend using a robots.txt file to block access to your images.
Create a great user experience
Great image content is an excellent way to build traffic to your site. We recommend that when publishing images, you think carefully about creating the best user experience you can.
- Good-quality photos appeal to users more than blurry, unclear images. In addition, other webmasters are much more likely to link to a good-quality image, which can increase visits to your site. Crisp, sharp images will also appear better in the thumbnail versions we display in our search results, and may therefore be more likely to be clicked on by users.
- Even if your image appears on several pages on your site, consider creating a standalone landing page for each image, where you can gather all its related information. If you do this, be sure to provide unique information—such as descriptive titles and captions—on each page. You could also enable comments, discussions, or ratings for each picture.
- Not all users scroll to the bottom of a page, so consider putting your images high up on the page where it can be immediately seen.
- Consider structuring your directories so that similar images are saved together. For example, you might have one directory for thumbnails and another for full-size images; or you could create separate directories for each category of images (for example, you could create separate directories for Hawaii, Ghana, and Ireland under your Travel directory). If your site contains adult images, we recommend storing these in one or more directories separate from the rest of the images on your site.
- Specify a width and height for all images. A web browser can begin to render a page even before images are downloaded, provided that it knows the dimensions to wrap non-replaceable elements around. Specifying these dimensions can speed up page loading and improve the user experience. For more information about optimizing your images, see Optimizing Web Graphics on the site Let's Make the Web Faster.
With image search, just as with web search, our goal is to provide the best and most relevant search results to our users. Following the best practices listed above will increase the likelihood that your images will be returned in those search results.