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.

maid service near Lake Forest ..

In The News:

FDA approves first human trial for Paradromics' brain-computer interface that could restore speech for paralyzed patients through neural technology.

New phishing platform QRR targets Microsoft 365 users across 1,000 domains in 90 countries. Learn how to spot fake login pages and protect your accounts.

OpenTable now uses AI to track your dining habits and share insights with restaurants. Learn what data they collect and how to protect your privacy.

Google's discontinued Nest thermostats still secretly upload home data to company servers despite losing smart features, raising serious privacy concerns.

New Android malware NGate steals NFC payment codes in real-time, allowing criminals to withdraw cash from ATMs without your card. Learn protection tips.

DoorDash confirms data breach exposing customer names, emails, addresses after social engineering attack. Learn how to protect yourself from scams.

Concerned about Google's AI scanning your Gmail? Learn how to disable Gemini features that access your emails, Drive files and Chat messages for privacy.

Google warns Android users about dangerous fake VPN apps hiding malware that steals passwords, banking details and personal data from phones and tablets.

Apple's digital passport feature lets iPhone users breeze through TSA checkpoints this holiday season using Digital ID technology at 250+ airports.

A new phishing scam targets family photos with fake "Cloud Storage Full" alerts. Criminals steal credit card information through fake sites. Learn protection tips.

South Korean scientists create ultra-thin fabric muscles that turn clothes into robotic assistants, lifting 33 pounds while weighing under half an ounce.

Archer Aviation has acquired Hawthorne Airport for $126M to launch an LA air taxi network ahead of the 2028 Olympics, featuring AI-powered eVTOL operations and next-gen aviation tech.

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

Fake AI apps disguised as "ChatGPT" and "DALL·E" are flooding app stores with dangerous malware that steals data and monitors users without detection.

Fake buyers demand specific vehicle reports from unknown sites to steal credit card information from car sellers, but warning signs can help identify these scams before paying.

Android users can now manage apps across multiple devices more easily with Google Play Store's updated remote uninstall button in the latest update.

NASA's Perseverance rover discovers shiny metallic rock on Mars that could be a meteorite from an ancient asteroid, containing high levels of iron and nickel.

Holiday scams spike during Black Friday and Cyber Monday as criminals exploit your leaked personal data. Learn how to protect yourself from fake stores and phishing.

Commerce Department proposes TP-Link router ban over Chinese security risks. Learn how this potential prohibition could affect your home network and devices.

Hyundai AutoEver America suffered a data breach affecting 2,000 current and former employees, exposing names, Social Security numbers and driver's license information.

Washington court rules automated license plate reader images are public records, even when stored by vendors like Flock Safety, setting precedent for transparency.

Fake airline texts claiming flight cancellations are targeting travelers with convincing scams. Learn how cybercriminals steal personal data and credit card info.

Discover how iOS 26's new Adaptive Power feature automatically extends iPhone battery life by learning your usage patterns and adjusting performance intelligently.

New TikTok malware campaign tricks users into running PowerShell commands that download Aura Stealer, which steals credentials and authentication tokens.

Gaia Family offers fixed upfront pricing for IVF cycles with unlimited embryo transfers and financial protection, partnering with over 100 U.S. fertility clinics.

Writing Effective ALT Text For Images

Web Development