Alt text is often misunderstood as an “SEO hack.” Its primary job is accessibility. When you write it well, more people understand your creative-including bots that index public content-without turning posts into keyword spam.
The template we teach internally
[Subject] + [action/context] + [essential on-image text]
Example: “Product manager highlighting a quarterly chart on a laptop screen; slide title reads ‘Activation +12%’.”
Do / Don’t
| Do | Don’t |
|---|---|
| Be specific about data that only exists in pixels | Dump 30 hashtags into alt text |
| Mention chart type if it helps (“line chart,” “heatmap”) | Start with “Image of…” every time-vary naturally |
| Reflect diversity respectfully (roles, not stereotypes) | Include sensitive traits unless visually critical and necessary |
Platform nuances (high level)
- Instagram: Alt text protects grid understanding when images break; pair with thoughtful feed composition.
- LinkedIn: B2B diagrams should restate key metrics in the caption body as well-many readers skim text-only feeds.
- X: Useful alt helps when images are paywalled or slow to load; see image sizing to avoid unreadable text.
Video thumbnails
If platforms let you set a thumbnail plus alt, describe the thumbnail moment viewers actually see, not the whole 60-second storyline-unless the video is extremely short.
QA before scheduling
- Read alt aloud-does it stand alone?
- Would a teammate understand the post without seeing pixels?
- Did you avoid unverifiable hype (“best ever”) in alt?
Frequently asked questions
- What is alt text on social media?
- Alt text (alternative text) describes an image for people who use screen readers or when images fail to load. It is additive to captions-not a substitute for writing good captions.
- How long should alt text be?
- Usually one or two concise sentences. State the subject, key action, and essential text that appears in the image-avoid stuffing keywords.
- Should alt text repeat the caption verbatim?
- No. Captions carry tone and hashtags; alt text carries faithful visual description. Some overlap is fine, but blind duplication wastes screen-reader time.
- Do all platforms expose alt text the same way?
- No. Field names, character limits, and whether alt travels on reshares vary. Test on each network you publish to.