An alt tag is a description of an image that are used within an HTML code in order to describe what is depicted on the image and what its function is on a webpage. Essentially, an alt tag is the text that gets displayed on a webpage in the event that an image does not show correctly or is currently undeliverable. It’s also the description that gets synthesized into speech when a user employs an assistive technology such as a screen reader.
To give you an example, an alt tag code would look something like this:
<img src=http://www.example.com/panda.jpg alt=”A photo of a panda bear in San Diego zoo" />
As you can imagine, alt tags are essential to accessibility because they provide an alternative means of displaying information about the images. Not only is this helpful for users for whom the images are not showing correctly, it’s also advantageous for users who are visually challenged because they can use the descriptions in order to better understand what the images are all about. Moreover, as will be explained later, implementing proper alt tags can also be beneficial for on-page search engine optimization (SEO), in addition to helping drive more traffic to websites.
Main Uses and Benefits of Alt Tags
Accessibility for the Visually Challenged
Imagine that a visually impaired individual is trying to access and obtain information from a webpage. In order to accomplish this, that person would have to use an appropriate tool like a screen reader, which is essentially a software application that transforms visual content into synthesized speech. The technology allows the person to listen to a webpage’s content instead of having to read it, but there’s a catch. Aside from the program’s actual quality, a software’s ability to produce a functional “voice” also depends on other factors, and these include whether or not the webpage content uses proper spelling, punctuation, headings, and alt tags for images.
Implementing alt tags for images are particularly important for users of screen readers because it is the only way for them to accurately obtain information about images that they cannot see properly. When no proper alt tags are used, a screen reader might simply identify the image using its filename or just mention the word “image” or something similar. With the help of alt tags, however, content providers can precisely describe the content of the images they use, helping visually challenged users to navigate their websites and to get the information that they need.
Alternative Source of Information
Aside from helping visually challenged users, alt tags can also be beneficial for users who are not able to see the images because they are not displaying as they should.
There are a number of reasons why certain images might not display as expected. The image file could be missing, for instance, or the user could have set the browser up to prevent images from loading in an effort to make webpages load faster. The user could also be using a security software that may incorrectly identify images as web beacons or tracking bugs, or the image might have a pathname that is not loadable in some browsers. Finally, a user might simply have a slow internet connection, or the website being accessed might be presently experiencing technical challenges. Alt tags can help users understand the content or message of the images when these images do not show up correctly due to any of the aforementioned reasons.
Better Search Engine Optimization
On top of improving accessibility and user experience, alt tags can also provide intrinsic SEO benefits for websites that implement them properly. This is because they also afford search engines like Google with useful information about the subject matter of the images.
It is worth noting how much artificial intelligence has improved over the years that we now have image recognition technologies that can—say—recognize if the same person is depicted in two different photographs. It does this by comparing the facial features of the subject individuals. However, search engine image recognition has yet to develop to such a level whereby it can interpret the actual content of the images. As such, Googlebot and other search engine crawlers still rely on tools like alt tags to be able to understand what the images are really all about or what they are trying to convey. They use the information contained in alt tags in order to determine the best images to return for search queries being entered by users.
As you can imagine, it’s not ideal to just leave search engines to interpret the content of your images on their own. They most definitely need a helping hand. You’ll have to make use of the right filenames and alt tags if you want to up your chances of ranking for particular keywords or search queries, Remember, proper implementation of on-page keywords still remains as an important search engine ranking factor.
Alt Tags Best Practices
Now that you know about the important functions of alt tags, it’s time to learn about the best ways to incorporate them into your webpages. Here are a few tips to help you get started:
Make Them Detailed and Informative
Alt tags should be highly descriptive, meaning they should satisfactorily describe the images, providing a clear picture about what is depicted on the said images. Remember, the description should be highly relevant to the subject matter, and it should provide value to users who might not be able to see the actual images on page.
Use Appropriate Keywords, but Don’t Go Overboard
Using proper alt tags can help you tell search engines that your images are relevant to particular searches being conducted by users. As such, if you have target keywords that are also relevant to the subject or theme of an image, you may use those keywords in your alt tag.
However, make sure not to stuff your alt tags with repetitive or irrelevant keywords. If you have an image that depicts a dog playing a ball, for example, stuffing your alt tag with unnecessary additional words like “canine,” “hound,” “mutt,” “pooch,” and “puppy” can result in negative user experience. Moreover, search engines may also perceive your webpage as being spammy, resulting in lower SERP rankings.
Keep Them Short
Go for short, impactful alt tags that can be understood well by users and can be indexed properly by search engines. Although many leading screen reader applications provide no limitations as to the length of the alt tags they will read, some programs actually truncate the alt tags when they are more than 125 characters long.
Experiment with Longdesc Attributes
There may be instances when an image actually warrants a more complex description. If this is the case, consider using a longdesc attribute or tag. When you use this, any assistive application that recognizes longdesc attributes will be able to inform the user that a lengthier description is available. For instance, a screen reader or browser may prompt the user to enter a key or click somewhere on the page so that they can access the long description. Here is an example of a code that uses a longdesc tag:
<img src= http://www.example.com/oceans.jpg =”A diagram detailing the depth of the world’s oceans.” longdesc=”oceans_longdesc.html” />
With the help of a longdesc attribute like the one above, the content provider can supply a longer description explaining the details of the diagram.
Images That Are Purely Decorative Should Reside in Your CSS
Typically, images can be used to convey messages to users or act as an additional content element in a page. If, however, an image is being used solely as a design element, it shouldn’t be in your HTML; it should be in your CSS.
Alt tags are an invaluable tool that can help you drastically improve user experience within your website while also gaining SEO points. Try implementing them today, and let us know how well they work for you.