When do I use Alt text vs captioning an image - or do I do both?
Doctor Digital Says
As video and picture based digital channels continue to dominate how we interact online, increasingly visuals play a significant role in communication, appearing on websites, social media, presentations, and documents. However, not everyone experiences the internet in the same way. Enter 'alt text' and 'image captions', two important elements that ensure content is inclusive and accessible for all users, regardless of their abilities.
In this blog we look at what they are and provide a guide on how to write them effectively and when to use them in your online content.
Alt text
Alt text, short for 'alternative text', is a concise and descriptive text that acts as a substitute for images, graphics, and other visuals on a webpage or document. This text is hidden in the HTML code and allows screen readers and assistive technologies to describe the visual content to users with visual impairments, or who might have specific preferences. By conveying essential image information, alt text ensures that everyone can understand and engage with the content equally.
Here are some tips for writing effective Alt text:
- Be descriptive: Provide a concise but detailed description of the image, including its purpose, key elements, and any relevant text within the image.
- Context matters: Consider the image's context and how it relates to the surrounding content. Ensure that the alt text conveys the image's role in supporting the overall message.
- Skip decorative images: If an image is simply for decoration and doesn't add any meaningful information, use empty alt text (alt="") to let screen readers skip over it.
- Keep it short: Aim for alt text that is no longer than a sentence or two. Avoid long paragraphs or redundant descriptions. If you need that many words to explain the image, think about adding more to your text or a different image to convey context.
- Use your keywords, but sparingly. Only include your article's target keyword if it's easily included in your alt text. If not, consider semantic keywords, or just the most important terms within a longtail keyword. For example, if your article's head keyword is "how to generate leads," you might use "lead generation" in your alt text, since "how to" might be difficult to include in image alt text naturally.
- Don't cram your keyword into every single image's alt text. If your blog post contains a series of body images, include your keyword in at least one of those images. Identify the image you think is most representative of your topic, and assign it your keyword. Stick to more aesthetic descriptions in the surrounding media.
- Review for spelling errors. Misspelled words in image alt text could hurt the user experience or confuse search engines crawling your site. You should review alt text like you would any other content on the page.
- Don't use 'Image of' or 'Picture of': Screen readers already announce that the content is an image, so there's no need to include phrases like 'Image of' or 'Picture of' in the alt text, just describe in simple detail what is in the image.
Image Captions
Image captions provide additional context and information about an image, benefiting not only users with a disability but also all users who might benefit from more context. Accessible image captions are not only descriptive but also helpful in understanding the image's relevance to the content.
Here are some tips for writing accessible image captions:
- Summarise the content: Write a brief caption that summarises the main message or purpose of the image in the context of the surrounding content.
- Provide details: Include any relevant details, such as names of people, locations, or objects, if they are crucial to understanding the image.
- Consistency with alt text: Ensure that the caption aligns with the alt text and doesn't contradict the information provided there.
- Avoid overloading with text: Keep captions concise and avoid overloading images with too much text, as this can be overwhelming for users.
How Alt Text Affects SEO
According to Google, alt text is used — in combination along with computer vision algorithms and the contents of the page — to understand the subject matter of images.
Alt text, therefore, helps Google to better understand not only what the images are about but what the webpage as a whole is about. This can help increase the chances of your images appearing in image search results.
With Google’s rollout of Search Generative Experience (SGE), high-quality and contextual alt text ensures your content is in the mix of the new AI-powered snapshot of key information.
For example, Google notes that its SGE can give people a well-rounded shopping experience with noteworthy options, product descriptions, pricing, and images in one single snapshot. If your product images have descriptive and specific alt text, you give search engines the context to know when to surface your product as a high-quality choice in someone's results.
When creating content on a topic, consider how your audience might prefer to find answers to their questions on that topic. In many cases, Google searchers don't want the classic blue, hyperlinked search result — they want the image itself embedded inside your webpage.
Another important thing alt text does for you is surface your images in search results, whether in Google Images or as image packs. Image packs are special results displayed as a horizontal row of image links that can appear in any organic position. And, images that appear in both types of search results are yet another way to receive organic visitors.
By adding alt text and image captions to your content, you'll create a more inclusive online environment for all users. To learn more, explore the Digital Ready guide to accessibility below. It provides resources and tools to meet accessibility guidelines and ensure accessible content for all. The great part about making your online content accessible is that everyone benefits in access and enjoyment, making your business and brand a more inclusive place.