Home
>
Web Development
>
Writing Effective ALT Text For Images

Writing Effective ALT Text For Images

Anyone who knows anything about web accessibility knows that images need alternative, or ALT, text assigned to them. This is because screen readers can't understand images, but rather read aloud the alternative text assigned to them. In Internet Explorer we can see this ALT text, simply by mousing over the image and looking at the yellow tooltip that appears. Other browsers (correctly) don't do this. The HTML for inserting ALT text is:

img src="filename.gif" alt="Alternative description goes here"

But surely there can't be a skill to writing ALT text for images? You just pop a description in there and you're good to go, right? Well, kind of. Sure, it's not rocket science, but there are a few guidelines you need to follow...

Spacer images and missing ALT text

Spacer images should always be assigned null ALT text, or alt="" . This way most screen readers will completely ignore the image and won't even announce its presence. Spacer images are invisible images that pretty most websites use. The purpose of them is, as the name suggests, to create space on the page. Sometimes it's not possible to create the visual display you need, so you can stick an image in (specifying its height and width) and voli?, you have the extra space you need.

Not everyone uses this null ALT text for spacer images. Some websites stick in alt="spacer image". Imagine how annoying this can be for a screen reader user, especially when you have ten of them in a row. A screen reader would say, "Image, spacer image" ten times in a row (screen readers usually say the word, "Image", before reading out its ALT text) - now that isn't helpful!

Other web developers simply leave out the ALT attribute for spacer images (and perhaps other images). In this case, most screen readers will read out the filename, which could be 'newsite/images/onepixelspacer.gif'. A screen reader would announce this image as "Image, newsite slash images slash one pixel spacer dot gif". Imagine what this would sound like if there were ten of these in a row!

Bullets and icons

Bullets and icons should be treated in much the same way as spacer images, so should be assigned null alternative text, or alt="". Think about a list of items with a fancy bullet proceeding each item. If the ALT text, 'Bullet' is assigned to each image then, "Image, bullet" will be read aloud by screen readers before each list item, making it take that bit longer to work through the list.

Icons, usually used to complement links, should also be assigned alt="". Many websites, which place the icon next to the link text, use the link text as the ALT text of the icon. Screen readers would first announce this ALT text, and then the link text, so would then say the link twice, which obviously isn't necessary.

(Ideally, bullets and icons should be called up as background images through the CSS document - this would remove them from the HTML document completely and therefore remove the need for any ALT description.)

Decorative images

Decorative images too should be assigned null alternative text, or alt="". If an image is pure eye candy then there's no need for a screen reader user to even know it's there and being informed of its presence simply adds to the noise pollution.

Conversely, you could argue that the images on your site create a brand identity and by hiding them from screen reader users you're denying this group of users the same experience. Accessibility experts tend to favour the former argument, but there certainly is a valid case for the latter too.

Navigation & text embedded within images

Navigation menus that require fancy text have no choice but to embed the text within an image. In this situation, the ALT text shouldn't be used to expand on the image. Under no circumstances should the ALT text say, 'Read all about our fantastic services, designed to help you in everything you do'. If the menu item says, 'Services' then the ALT text should also say 'Services'. ALT text should always describe the content of the image and should repeat the text word-for-word. If you want to expand on the navigation, such as in this example, you can use the title attribute.

The same applies for any other text embedded within an image. The ALT text should simply repeat, word-for-word, the text contained within that image.

(Unless the font being used is especially unique it's often unnecessary to embed text within images - advanced navigation and background effects can now be achieved with CSS.)

Company logo

Websites tend to vary in how they apply ALT text to logos. Some say, 'Company name', others 'Company name logo', and other describe the function of the image (usually a link back to the homepage), 'Back to home'. Remember, ALT text should always describe the content of the image so the first example, alt="Company name", is probably the best. If the logo is a link back to the homepage then this can be effectively communicated through the title tag.

Conclusion

Writing effective ALT text isn't too difficult. If it's a decorative image then null alternative text, or alt="" should usually be used - never, ever omit the ALT attribute. If the image contains text then the ALT text should simply repeat this text, word-for-word. Remember, ALT text should describe the content of the image and nothing more.

Do also be sure also to keep ALT text as short and succinct as possible. Listening to a web page with a screen reader takes a lot longer than traditional methods, so don't make the surfing experience painful for screen reader users with bloated and unnecessary ALT text.

This article was written by Trenton Moss. He's crazy about web usability and accessibility - so crazy that he went and started his own web usability and accessibility consultancy ( Webcredible - http://www.webcredible.co.uk ) to help make the Internet a better place for everyone.

spotless home service Lake Forest ..

In The News:

A Columbia University breach exposed names, Social Security numbers and academic records of nearly 869,000 people, with notifications beginning in August.

Rental car drivers use AI-powered apps like Proofr to protect themselves from unfair damage fees as major companies deploy automated inspection tools.

Fox News' AI newsletter brings you the latest on technology advancements around artificial intelligence.

OnTrac data breach between April 13-15, 2025, exposed personal information of over 40,000 people including Social Security numbers and medical records.

A woman named Wika announces her engagement to an AI chatbot sparking worldwide debate about virtual relationships and technology.

The notorious people search site National Public Data relaunches despite a previous breach affecting 3 billion individuals, raising fresh privacy concerns.

Revolutionary TRAUMAGEL gel controls life-threatening bleeding from gunshot wounds and traumatic injuries, helping first responders prevent prehospital deaths.

Protect your home network by enabling proper encryption, creating strong passwords, checking connected devices and using VPN and antivirus software.

The Navy's solar-powered Skydweller drone flew nonstop for 73 hours in Mississippi, proving renewable energy can power long-endurance military missions.

Moving and downsizing expose seniors to identity theft and scams as data brokers collect real estate records and personal information to sell to criminals.

ShengShu's Vidar technology revolutionizes humanoid robot training by using AI-generated synthetic video, reducing required training data from hours to just 20 minutes.

Apple's older Mac computers face security risks without regular updates, but 10 essential tips including FileVault encryption and strong passwords can keep aging Macs protected.

Self-driving trucks from PlusAI could reshape freight transportation by 2027, addressing driver shortages and reducing logistics costs for businesses.

Solar farms are turning to sheep instead of mowers to cut grass under solar panels, lowering costs, reducing emissions and creating new income for farmers.

Fraudsters posing as local officials are making fake calls about missed jury duty, demanding payments in a rising scheme that exploits fear of arrest.

Honeywell Aerospace engineers developed a "surface alert system" that gives pilots two aural warnings when they are 15 and 30 seconds away from a collision on the runway.

Anonymous researcher has scraped public Spotify accounts of politicians and celebrities, highlighting major privacy risks in default platform settings.

AI chatbot toys marketed as screen-free playmates could undermine children's empathy and critical thinking skills, according to pediatric specialists.

TransUnion confirms a major data breach affecting 4.4 million U.S. consumers after hackers exploited third-party Salesforce apps to steal personal info.

Scammers use fake DocuSign emails claiming Apple Pay charges to steal personal information using fraudulent phone numbers and fake receipts.

Stay up to date on the latest AI technology advancements and learn about the challenges and opportunities AI presents now and for the future.

Farmers Insurance confirms data breach affecting over 1.1 million customers nationwide, exposing customer info including addresses.

The iconic Mary Kay pink Cadillac goes electric with the Cadillac Optiq, available only to the company's top 1% of sales force performers.

Cybercriminals abuse trusted Intel driver to gain kernel access and shut down Windows Defender, enabling undetected malware deployment since July 2025.

Using email aliases for online shopping and subscriptions can protect your privacy by preventing companies from linking your activity across websites.

Writing Effective ALT Text For Images

Web Development