Alt Text
Alt text is a written description attached to an image so screen readers can voice it and platforms can index the image for search.
Alt text (alternative text) is a short written description added to an image that a screen reader speaks aloud for a person who cannot see the image, and that also shows up if the image itself fails to load. It has been a basic web accessibility requirement since long before social media existed.
On social platforms alt text does double duty: Instagram and Pinterest both use it as extra searchable text about an image, on top of the caption, which means a well written description can help a post surface in image search even when the caption never mentions the object in the photo. Most platforms auto-generate a rough alt text using object recognition, but that automatic version is usually vague ('may contain: person, outdoors') and worth replacing.
Good alt text describes what matters in the image in one or two plain sentences, skips 'image of' or 'picture of', and never stuffs it with unrelated keywords, which platforms treat as spam.
Examples
- Replacing a vague auto-generated tag like 'may contain: food' with a specific description on a post that reaches 5,000 followers.
- A furniture brand adding alt text to 200 product photos and seeing a measurable rise in Pinterest search impressions the following month.
Related terms
Captions and subtitles are on-screen text of a video's spoken words, added for viewers who watch on mute or in a different language.
Aspect ratio is the proportion between an image or video's width and height, written as two numbers such as 9:16, 1:1, 4:5 or 16:9.
Number of unique users who saw your post at least once.