Search engine optimisation is not only about words on a page. Images are content too, and you can see traffic growth if you ensure you not only optimise images but remember to use them. I’m going to share some analysis with you that I have done across four websites, to demonstrate the different results you can see from Google Images, based on what Google Analytics reports.
This data is found in Traffic Sources and under referrals, where you can view the referral path. Simply set a filter for “images”, which is the name of the referring script Google uses within its Images search section.
Service company benefits from optimisation
The graph below shows a year on year comparison for a website that sells security services. Last year, very little traffic came from Google Images. The reason for this was the images on the site were randomly named and not optimised.
The images on the site were not changed much – none were added or removed, just re-named and optimised. What is interesting about this graph is that the optimisation of images helped to get a 400% increase in traffic from Google Images, but the value of each visit dropped. This is clearly because the likely intent of people searching for images does not often match the offering on the website. I’ll compare this with other sites below.
A mixture of products and services
This year on year comparison shows growth in traffic for a website that sells a travel-related product. This growth comes partly through re-optimisation of existing images and the pages they are on (it correlates with a general growth in the site through normal SEO and content development). The growth is also due partly to new content and images being added to the site.
Compare this graph with the one above. In this case, the increase in image referrals has also resulted in an increased visitor quality. This can also be explained quite simply. This website sells a specific travel-related product to a particular interest group. The article pages and the product pages offer a good match to the people who are likely to be searching for these images. In fact, when I look more closely at the landing pages related to this traffic, the pages related to actual products retain more traffic than the articles, which tend to use a general image for illustrative purposes.
Affected by Penguin, but not in Google Images
This website was affected by Google’s Penguin update in April 2012. The traffic dropped by half in May due to a sudden loss in rankings for top keywords. However, in that time, traffic from Google Images was unaffected.
In fact the referrals from Images improved because we added images to old pages that had none and optimised images on key landing pages. For some keywords where Penguin was de-ranking the site in the main text results, the site has been appearing in the top five results in Images. The retention rates for this traffic also improved, because this is a travel-destination site, where the pages are largely about the destination. Therefore, people searching for these images are generally interested in the kind of information offered on the landing pages.
Product searches bring a low bounce rate
This website is purely product based. Even the articles relate to the products it sells, so anyone typing the keywords related to this business is looking for the product – maybe a price, maybe to see what it looks like.
This website has a respectable bounce rate when you compare it with the other sites above. Again, this is because the page matches the intent of the searcher. Maybe they are looking for products by type or name and then clicking on the product that catches their eye – a visual comparison search rather than a price comparison.
If you had any doubt after this that Images are not a key part of your content-driven search marketing strategy, let me tell you that this fourth site has an overall bounce rate of 56%, so a 36% bounce rate from the images is contributing excellent value.
Image optimisation tips
- Make sure you use images on every page.
- Use file names relevant to the image and to the content of the page.
- Use descriptive ALT text. (Which helps blind readers too.)
- Make sure the image is indexable – putting it in a Flash movie is no good.