Alt text is a short text description for a photo on a web page. This description explains the photo to search engines and the disabled.
Before I dive much further I want to clear up some confusion you may have. “Alt text” is short for “alternative text”. It is also commonly called the alt attribute or the alt tag. Calling it the alt attribute refers to the technical method of assigning alt text to a photo. Calling it the alt tag is a misnomer. There is no such thing as an alt tag. I would love to know where this misconception originated. It goes back long before I started building websites.
The Role of Alt Text in SEO
Photos are a critical part of SEO. Your imagery helps separate you from your competition. This wow-factor will impress your average visitor, but a search engine cannot see the image. Think of a search engine as a blind person. They need a text description to understand the meaning of the photo. Providing a description for the photo makes them more discoverable on the web. If a user sees your photo in Google Image Search they can then browse to the original page for that photo.
Tips for Writing Alt Text
- Keep the description short. I recommend you keeping it around the length of a tweet (but don’t shorten words since there is no limit).
- When writing alt text think how you would describe the image to a blind person. That is the original purpose of alt text.
- Do not include “Photo of” or “Image of”. Search engines and screen readers already know it’s an image.
- If the photo has text, use that as the description.
- If possible, include the focus keyword.
- Do not stuff many keywords.
- Do not write the description like it is a mouse over tooltip. Use the
titleattribute for a tooltip. This practice began when IE was the dominant browser since that was the behavior in IE. IE stopped displaying these a tooltip for alt text in IE8.
- For photos that are purely decorative simply use a single space as the alt text. This implies that this photo is not important to the content on the page.
Now that you know just how important alt text is to a photo be sure to use the Image SEO Tool to check a page on your site. You want to verify that every image has alt text. Specifying alt text on every image will help improve your SEO efforts.
Thank you and keep building your brand.