I’ve been asked a couple of times recently about how best to use alt text (or tags) when creating social media posts, this post covers why adding alt tags should become a habit, the main points to remember and tips on best practice.
It’s important to say that I am still learning, still trying to be and do better on accessibility. If I’ve missed anything – tell me. This is an evolving area, features and options on platforms change.
What is alternative text online?
Remember in the olden times of dial up internet when images regularly didn’t load and empty boxes appeared on screen? No one knew what the images were meant to be. Alternative text, to give its full title, is a description in text form of what the image should be and is part of the code of the page. It’s not the same as a caption and it’s not visible to anyone not using some kind of screen reader technology.
In the PR and creative sectors, we’re probably most familiar with alt text in relation to SEO. Hubspot, Yoast, Moz all have blogs and articles on the importance of using alt text for SEO, but only Moz mentions right at the start that it is “first and foremost” about accessibility.
Is an image description the same as alternative text?
An image description is usually typed into a post and is visible to everyone. It’s a plain text description of an image, GIF, or video. It’s different from alt text in that it’s not a part of the page code, and they tend to be longer descriptions which are part of the main post, or added on like an extra tweet if space is an issue.
Do you still need a caption?
It’s important to remember that an image description or alt-text is a way for blind and visually impaired people to know what the image is, a caption is rarely an image description, often it’s a piece of supplementary information relating to the article, blog or post. Adding a caption is still a good idea, if a caption is relevant. A screen reader will usually read the alt-text and then the caption.
Alt text on social platforms
The ironic thing about accessibility options on most social platforms is that they’re not obvious and easy to use. Because accessibility is still most often thought about after the fact the route to putting them in place is sometimes clunky and unclear and limited. Plus the options are different on each social platform, and then of course, there is the fact that many agencies use social scheduling tools, not native posting, and each tool is different again. Ad infinitum.
And one big thing to keep in mind – and this is something I see a lot from the PR community – is that images with text are not accessible. There is a real trend in creating social media images for events, or words of inspiration or quotes as images. Unless you repeat the information in those images in the post or in alt-text then it is not accessible.
Facebook is one of the most straightforward and obvious. When you add an image to a post, click edit and a window opens with options, the bottom one of which is alternative text’ add your description and hit save. However, this only works for pictures, if you post a gif make sure to add an image description in the post.
Additionally, at the start of this year, Facebook announced an upgrade to it’s automated alt-text (AAT) function. This link highlighted here explains in detail the changes, but in summary Facebook has expanded the number of items its automated system can detect and added the function for more specific descriptions. For example, identifying the main focus of an image and how many and where people are placed within it.
Twitter has improved its alt-text function. Early last year it enabled the option to add alt-text to gifs. It was a feature I’m glad they added. I am a lover of gifs but the lack of accessibility has been problematic. Like Facebook, alt-text is easy to add. There is an in-depth article specifically on alt-text linked here which covers the multiple different ways to add alt-text.
One big thing to note is the new and growing trend of using images with a lot of text. I’ve seen these used for events, and they usually look like this:
[Image description]

Text heavy images are largely inaccessible. You can add alt-text, but keep in mind that most screen readers read 125 characters and the text on your image will likely exceed that, especially images which are advertising events; speaker photos, names, dates, times, a quote from a speaker. That’s a lot of information to put into a specific alt-text feature. To avoid this there are two alternatives; add the same information that’s in the image to the post, or create a thread if there’s not enough characters left in the original tweet, or, go with a less text heavy image. Keep it clear, simple and don’t rely on it as the key medium to share vital information.
As you’d probably expect a visual platform like Instagram doesn’t have great in built accessibility. However, you can add alt-text to images on Instagram. Go through the normal process of uploading a photo, when you get to the stage of writing a caption look down the page to find ‘advanced settings’, from here you can see ‘Accessibility’ and underneath, ‘write alt-text’. You can also add an image description to the caption – this is becoming increasingly common as it does offer more space to describe the image.
LinkedIn was late to the alt-text party. In 2019 it added auto-generated alt-text if it appeared an image wasn’t given alt-text by the author, but this seems hit and miss as do the notifications to say whether alt-text has been automatically assigned. Like Facebook and Twitter you can add alt-text when you upload an image – click edit in the top left hand corner of the photo. Unlike the other two platforms, LinkedIn does put a character limit of 125 on your alt-text. Helpfully, this function is only available on desktop, you cannot (yet) add alt-text on mobile uploads.
TikTok
At the end of 2020, TikTok added a text-to-speech function to improve its accessibility, but beyond that I can’t find anything which indicates you can add alt-text to videos.
Clubhouse
I’ve written an entire blog post about the lack of accessibility on Clubhouse which is linked here.
What about alt-text on social scheduling tools?
Most PR folks use some kind of social media scheduling tool – Hootsuite, Buffer, Agorapulse, ConstantCal, most of these have an option to add alt-text when you add a post to the calendar. Each platform has information on how to add alt-text on its support pages but it varies on detail and helpfulness. Buffer, for example, includes one small section about alt-text under their ‘Scheduling Posts’ section, a blog post covering the announcement from 2017 linked here has more details than their own website.
Hootsuite, on the other hand, mentions accessible social media on multiple support pages from tips on inclusive design to including it as an instruction on each of its ‘create a [social media] post pages’. In theory, the option to add alt-text should be obvious when you create a new post, but that’s not necessarily the case. However, most of the major schedulers seem to have caught up on having some kind of basic accessibility in place.
Alt text dos and don’ts
As I mentioned at the start of this article, best practice with accessibility is an ongoing process, if your social team is spending time keeping up to date on trends and platform developments, make sure that accessibility is a core part of that research and upskilling work. Apps update and change, and as more people realise that better accessibility works for everyone and that excluding millions of people is no longer ok, expect it to take a big and more central role in social media best practice.
- Do describe the image you’ve posted.
- Don’t add additional words which aren’t in or relevant to the image you’re describing. For example, ‘Image of’ or ‘graphic shows’ in alt-text, screen readers can recognise that what they’re describing is an image.
- Do make sure you have duplicated any text on an image within the alt-text, remember, if there is a lot of text you will need to add this information in another way.
- Do use clear and plain language including proper punctuation.
- Don’t SEO the crap out of your alt-text, remember its primary purpose is accessibility.
- Do balance detail, relevance, and specificity.
- Finally, do keep going – it will take time to make alt-text and image descriptions a habit. Add it as a checklist item on process documents, put an accessibility column into a spreadsheet if that’s what you use – make it a visible element of your social media practices.