Learn how to write alt text that serves both accessibility and SEO purposes effectively.
What Alt Text Really Does
Alt text serves multiple critical functions. For accessibility, screen readers announce it so blind and low-vision users understand images. For SEO, search engines use alt text to understand image content. As a fallback, it displays when images fail to load. For context, it provides information for users who disable images.
The Science of Good Alt Text
Research shows descriptive alt text increases image engagement by 35% while improving both accessibility and SEO rankings.
Writing Effective Alt Text
Good alt text describes the image content directly, like saying a woman typing on laptop rather than just image or photo. It provides context such as Ellen Johnson, CEO, speaking at conference to include who and what. It remains concise, usually 40-125 characters. It uses natural language as you would speak. It avoids redundancy by not starting with image of. It includes relevant keywords when natural.
Common Mistakes
Do not leave alt text blank for decorative images, instead use empty alt. Never write just Image or Photo. Avoid keyword stuffing. Do not write overly long descriptions. Never assume context others can see.
Decorative vs Functional Images
Decorative images are purely for visual appeal with no information loss if removed. Use empty alt for these. Functional images convey important information and need meaningful alt text.
Conclusion
Good alt text is a cornerstone of accessible web design. It helps users with disabilities access your content while improving SEO performance.