May 07, 2009
If your site’s images are not optimized, numerous opportunities to attract visitors are wasted. To be a source of targeted traffic, images first have to be seen by search engines. And, if your images are not designed correctly, you are missing prospects who would arrive from: searches that include image results, image-specific search engines, and third-party image-hosting sites.
Find out the key factors to getting the most out of your site’s images, and ultimately, enticing as many visitors as possible to your site. Includes proof of optimization impact; advice on what prospects want to see.
A picture can be worth a thousand clicks. It can stand out, attract attention, and communicate faster than words. Your site’s images -- like the rest of its content -- are a valuable resource that you can leverage for capturing targeted traffic.
Once your Web pages are optimized, and you’re starting see positive results, optimizing your images can push your efforts further. The traffic can come from:
o Web searches that include image results
o Image-specific search engines
o Third-party image-hosting sites
Don’t underestimate the popularity of image-specific searches. Google Image Search was the 12th most popular website in the US in for the week ending on April 11, 2009, according to Hitwise. Also, “the big thing that most people don’t realize is, even though image search traffic volume is much less than Web search traffic volume, the competition for that volume is less,” says Eric Enge, President, Stone Temple Consulting.
However, you do not want to focus on optimizing images until the rest of your site is in good order. For example, a site’s text and link structure should be well-designed before its images are optimized.
Below, we outline the key factors in optimizing your site’s images. We also look at the potential impact of optimizing images through a mini Case Study, and outline a few other strategies that marketers are using. Take a look if you want to pull more natural traffic from resources you’re already hosting.
What the Engines See
Search engines cannot accurately discern an image’s content by looking at the image itself. Instead, they rely on data about the image to help them decide if an image is relevant to a search query. Below are the most important factors and data that search engines consider.
o Accessibility - Most importantly, you need to make sure that search engine spiders can see and index your images. Images that are displayed in a Flash file, or are dynamically loaded from a separate database, will not be indexed. The most easily indexed images are coded onto static HTML pages; they reside on the same server as the website.
o File name - an image’s file name should contain keywords related to the image, separated by dashes. Many digital cameras assign long irrelevant names to images, such as “img0032.jpg.” Change these to reflect the image’s attributes, such as “red-baseball-helmet.jpg.”
o Title tag - the title assigned to an image in its HTML tag should be a relevant description of the image. Titles appear when an image is moused over. They should be no longer than a sentence, or about 10 words.
o Alt tag - the “alt” portion of the image’s HTML tag should a relevant description. The alt text appears when an image fails to load. It should be no more than a long sentence, or about 20 words. Alt tags are important and often overlooked.
“I don’t think I can remember an instance where we’ve met a client and done a site analysis, or looked at an image gallery they have, and they had all the alt tags filled out. Literally never are the alt tags filled out,” says Andrew Melchior, CEO, Dream Systems Media.
o Context - an image and its metadata should be consistent with its page’s content and metadata. Relevant text surrounding the image, such as a text caption or description, will help improve the image’s relevance to target keywords. Also, it is important to not “overdo” the number of images on a page.
o Image links - linking your images to other sources of relevant content on your site will also improve the image’s relevance to target keywords. Such sources could be a product page, or a definition of the picture on an optimized page.
o Size - images with large file sizes take longer to load and can drag down a page’s overall performance, which can affect its ability to rank well. However, depending on the industry, your customers may be willing to wait for preferred larger, high-quality images.
o Quality - a compromise has to be struck between an image’s quality and its size. A high-quality image can catch a user’s eye and draw him to click on it over other images. Large images load slower.
o Geo-tags - attributing longitude and latitude coordinates to an image may improve its relevance for searches about that region, but only if that image is truly related to that area. Only very location-specific images should be geo-tagged. (See links below on how to geo-tag images)
Impact: Case Study Example
To illustrate the impact that optimizing images can have on a website, we talked to Rory Burrill, Director of Consumer Health, Logical Images. Logical Images offers several software tools that make use of its archive of over 50,000 health-related images.
VisualDxHealth, Logical Images consumer website, houses more than 2,000 images of mostly skin-related diseases. The site’s revenue model is advertising-based, and also promotes Logical Image’s paid professional products.
Burrill and his team initially launched the site in 2007 without optimizing most of the images. The images were displayed in a “pretty complex Java application” and had “cryptic” labeling, he says. The team set out in Fall 2007 to change that. Below are the changes they made and the results they saw.
o High-quality shots
The team was lucky to have a large database of images to pull from. They picked the cream of the crop for VisualDxHealth. This was sure to please site visitors, and the high-quality images have the added benefit of attracting eyes, Burrill says.
In an image search “consumers are going to look at the whole spread of images and not necessarily just click on the first one,” Burrill says. “They’re going to find the best image on that page.”
o Make images accessible
The team stopped using the Java application to display images, and started using basic HTML to make the images more easily seen by search engines.
o Naming and alt text
Due to the number and importance of VisualDxHealth’s images, the team has dedicated image archivists on staff. These specialists worked with Web engineers and medical editors to correctly name images, and add relevant alt text.
An example of the alt text: “This image displays small, slightly elevated lesions and scars in an adult with chronic acne.”
o Be patient
The changes took about three months to make, but it took twice that long for the search engines to catch on, Burrill says.
“The indexing of images is a slow process, and I think it’s even slower than standard text indexing. It took the better part of about six months for Google specifically to get through our images and index them.”
VisualDxHealth experienced about 500% growth in site traffic from Q3 2007 to Q4 2008. Most of that was due to image-search traffic, Burrill says.
“During November 2007 to March 2008, we saw a 2,229% increase in referral-based traffic directly linked to Google Images. Of the overall total site traffic growth during this period, nearly 70% can be attributed to growth from image search.” Google and its image search tool account for about 90% to 95% of all of VisualDxHealth’s image traffic, Burrill says.
The pace of that growth has slowed as the majority of VisualDxHealth’s images have been indexed. Now, about 24% of total site traffic is associated with image search, Burrill says.
o Impact of Universal Search
Since Google’s 2007 Universal Search announcement, some search engines now display results for images, news and videos, mixed with their Web search results. Since optimizing, some of VisualDxHealth’s images have made it to the first page of Google’s Web search.
“A great example of that is the term ‘kerion’. That’s a disease we cover. It’s a skin condition. We were in the results for kerion. They turned on Universal Search, and we had two of the top four images for universal search…This is one of our top-performing keywords now and in the top 20 pages for traffic,” Burrill says.
Getting More Impact
The marketers we spoke with mentioned several strategies that could improve the performance of your image SEO. Here are two we’ve highlighted:
Strategy #1: Host images at sharing sites
There are both free and paid services that will host your images online. They services offer a wide range in options, such as social media components and search-friendliness. These third-party sites give your images another chance at ranking in search engines. They can also reach people who use the sites directly.
These sites include:
- Flickr (Yahoo!-owned)
- Picasa Web Albums (Google-owned)
Note: Using Flickr for commercial purposes is against its terms of service (see links below). However, we have found accounts that appear to be managed by businesses and, while they do not sell directly from Flickr, they do link to a product category page (see the Urban Outfitter’s link below).
Flickr is considered one of the most popular, and Chris Silver Smith, Director of Optimization Strategies, KeyRelevance, says that it is well-designed for SEO. “Flickr has been engineered to be very search friendly,” he says.
When uploading images to these sites, fill out all the available fields of information. That includes page titles, photo descriptions, photo tags -- everything. The more relevant information you can include on the page that’s hosting your image, the better (without stuffing keywords or being spammy). Be sure to include a link to the portion of your website that is most relevant to the image. Note: the links are often tagged “no-follow” and, therefore, do not pass on “link juice.”
Strategy #2: Add more images
This strategy falls in to the “obvious” category, but it should be noted that marketers who do not operate image-intensive businesses, or do not have a large product line, can benefit from adding optimized images to their websites.
“So if you’re a boring factory making a mechanical doodad, even that can be interesting. Even though you only create one doodad, perhaps there’re a number of steps in the fabrication process. So you could document the process, and there would be interest to your clients as to how you created such a thing,” Smith says.
Other images can include pictures of your executive team, clip art and stock photography. If you sell a service, you can take pictures of your employees providing the service.
Strategy #3: Create individual images for pages
On some websites, when an image is clicked, the user is taken to a webpage that contains nothing but the image. This is not optimal, Smith says, and some marketers instead create a unique HTML page for each image on their sites.
These pages are optimized for keywords related to the image. For example, a webpage with an image of a black dress would have “black dress” in its H1 tags, page title, text description, etc. The page would not have any other content.
These pages should be linked to from your website so that search engines can easily spider them. They should also link back to a relevant portion of your website, so if users find them through a search engine, they can click to your main website.
Useful links related to this article:
Flash and SEO Primer Part I
Flash and SEO Primer Part II
Hitwise: United States top 20 sites & engines
How to Geotag Images
Flickr: Community guidelines
Flickr: Urban Outfitters Europe product
Flickr: Whole Foods Market PN region
Picasa Web Albums
Stone Temple Consulting
Dream Systems Media
Chris Silver Smith