WordPress SEO Tutorial updated February 2014
Alt text or alternative text is the text used to describe what an image is about.
For example the image to the right of this text (URL to the image: http://stallion-theme.co.uk/wp-content/uploads/stallion-responsive-wordpress-theme-200×150.png ) has alt text “Stallion Responsive Theme”.
You can view the code for the image below, with WordPress this is about as simple as it gets when WordPress adds an image to a post via the Add Media button.
<img src="http://stallion-theme.co.uk/wp-content/uploads/stallion-responsive-wordpress-theme-200x150.png" alt="Stallion Responsive Theme" width="200" height="150" class="alignright size-post-thumbnail wp-image-491" />
WordPress SEO Alt Text Value
Alt text associated with images is very important SEO wise, Google uses it to associate SEO ranking to the image and to the page the link is on.
Google also treats the alt text of linked images in a similar way to the anchor text of text links (hyperlinks). An image link is basically a text link (hyperlink) where the anchor text has been replaced by an image (see the linked image to the right and the code below), since an image link tends to lack anchor text, Google uses the alt text to determine what SEO value should be passed via the link.
<a href="http://stallion-theme.co.uk/"><img src="http://stallion-theme.co.uk/wp-content/uploads/stallion-responsive-wordpress-theme-200x150.png" alt="Stallion Responsive Theme" width="200" height="150" class="alignright size-post-thumbnail wp-image-491" /></a>
The image link to the above right is equivalent to this text link Stallion Responsive Theme (code for this text link below).
<a href="http://stallion-theme.co.uk/">Stallion Responsive Theme</a>
It’s difficult to test the relative SEO value of a text link with relevant anchor text to an image link with relevant alt text, I work with the assumption because alt text is semi hidden Google will give more SEO value to anchor text (basically anchor text has more SEO value than alt text when linking out, so if the link matters try for a text link first).
When writing articles if you can add at least one image (not linked) and one linked image (can be to another page on your site) with relevant SEO’d alt text you’ll help your articles rank better in Google and gain image SERPs as well. If you use the Stallion Responsive Theme the SEO Posts Widgets (like the Popular Posts widget on the right sidebar of this site) can include linked images (the thumbnails) with relevant SEO’d alt text.
Don’t Keyword Stuff or SPAM Alt Text
Before you go of keyword stuffing image alt attributes for improved SEO results please remember it serves a purpose beyond telling Google and other search engines what an image is about:
Wikipedia: Alternative text is text associated with an image that serves the same purpose and conveys the same essential information as the image. In situations where the image is not available to the reader, perhaps because they have turned off images in their web browser or are using a screen reader due to a visual impairment, the alternative text ensures that no information or functionality is lost. Absent or unhelpful alternative text can be a source of frustration for visually impaired users of the Web.
The image to the right is a screenshot of the Stallion Responsive linked image above using a browser extension to turn images off, this is what a user would see if they used a browser with images turned off.
As you can see the Alt Text (Stallion Responsive Theme) is still visible, so take this into account if you do go the alt text keyword stuffing route, you’ll really irritate your visually impaired visitors.
WordPress Media Library and Alt Text
Unfortunately WordPress does a rubbish job of dealing with alt text of images added via the WordPress Media Library. As I added the last image with filename seo-alt-text.jpg I took a screenshot of the default WordPress output (left side of the image below). WordPress uses the filename minus the extension (seo-alt-text) as the TITLE attribute and adds nothing to the ALT attribute box!
To SEO our images we have to manually add relevant alt text. Because I create images with SEO’d hyphenated filenames (Google treats the hyphen as a space in image filenames: Google reads seo-alt-text as seo alt text) I edit the title attribute box and replace the hyphens with spaces and uppercase the first letters (no SEO value to uppercase, just my preference) and copy the title attribute content to the alt attribute text box (the right side of the image below shows the SEO version).
If you’ve been adding images to WordPress using the Add Media Library button etc… and didn’t manually add relevant alt text to your images, you won’t have a fully SEO’d site and should manually edit all your old images to include relevant alt text. Stallion Responsive has a built in feature that adds an alt attribute form to the Media Library (under “Media” >> “Library”). See the screenshot below, the “Image Alt Text” form box is for adding relevant alt text to the images added to the WordPress Media Library.
Alt Text Added to Text Links SEO Test
You might be tempted to add an alt attribute (alt=”SEO Keywords”) to a text link like I’ve added to this text link: Alt Text SEO Test. View source of this link and you’ll see a unique made up keyword within the alt=”” part of the text link. On February 11th 2014 (when I edited this SEO article) the made up keyword had no results in Google, when this article is indexed by Google IF alt text added directly to hyperlinks have SEO value you should find.
This post being found for the relevant keyword in Google and/or the post the link is to found for the relevant keyword in Google.
Very confident this won’t ever occur, alt text within a link (as above) isn’t a valid use of alt text (should only be added to images and image links) and to date (had multiple SEO tests like the one above running for years) Google ignores it.