Why Care About Image Search?
Optimizing your images with file names and good alt tag descriptions is another easy way to let Google know the theme of your web pages, which in turn improves rankings. The result: more visitors!
Here’s what you need to know.
The first three points are considered critical to improving image search rankings.
POINT ONE – Use a Descriptive File Name
The file name should always include keywords that are relevant to the image and are words you want to be found for.
A file name like DSC1232.jpg doesn’t tell Google anything useful about the image! And use dashes or underscores in the file name to separate words so the Googlebot can easily parse it.
- GOOD: high-quality-red-womans-shoe.gif
- CONFUSING: highqualityredwomansshoe.gif
POINT TWO – Add Alt Text That Describes the Image
The Alt Attribute text (sometimes erroneously described as an “alt tag”) should describe the image in a simple manner. Use the keywords that are relevant to the image description, and where possible, the text should include the keyword phrase the page is optimized for.
By that I mean the keyword is used in the Title tag, within page content, and is used in links pointing to the page. But don’t “stuff” the Alt Attribute text with keywords, just use one, two or three at the most.
While the Alt tag doesn’t contribute very much to ranking in Google’s main index, Google implies that it helps in image search ranking.
POINT THREE – Ensure Image Relevance Maps to the Page Content
It may go without saying but the image should be relevant to the text content on the page. Where possible include descriptive text or captions on the page shown near the image, as that also helps Google understand what the image is about.
This descriptive text should contain the same keywords used in the Alt tag and file name.
It also helps when providing a link to a full-size image to do this: “Click here for full size image of Polycom Speakerphone” — instead of “Click for full size” or “enlarge”.
POINT FOUR – “Harmonize” the Alt Text, Filename, and Page Text
It may seem obvious, but for maximum effectiveness use the same keywords in the Alt Attribute text, filename, and page text close to the image.
Check out Matt Cutts Video on Image Search
POINT FIVE – Include Image Properties
Because Google is now factoring in page download times as part of their ranking, images should be optimized for fast download times and the image height and width should be specified in pixels in the HTML (that helps the browser render the image more quickly).
POINT SIX – Don’t Block the Bots from Your Images Directory
Believe it or not some sites exclude search bots from indexing their images directory. Why? I don’t know. Be sure and allow engines to index your /images directory.
POINT SEVEN – Optimize Images to be Fast-Loading
On mobile, page speed is critical. Images not optimized for fast downloading can hurt your website’s performance not only for visitors but also in its search ranking potential because Google now includes page speed as a ranking factor.
A page needs to load in 3 seconds or less – use this tool to check your page’s download speed.
Learn how to optimize your images for speed by following the steps in this article on image size optimization.