What good alt text does
Imagine reading the page aloud to a friend over the phone. Where an image carries meaning, you would describe it briefly. That description is the alt text. It should convey the purpose of the picture in the context of the page, not every visual detail.
A photo of a technician fitting a water heater on a service page might have alt text such as Technician installing a tank water heater in a basement utility room.
How long and how detailed
Aim for a short phrase or one sentence, commonly under about 125 characters. Skip the words image of or photo of, since assistive software already announces it is an image. Be specific rather than generic: water heater installation beats service.
Mention a keyword only if it naturally describes the image. Stuffing a list of terms helps no one and can look manipulative.
Different image types
For a logo linked to the home page, the alt text should say the business name, and perhaps home. For a button that is an image, describe the action, such as Call us, not the icon shape. For charts or infographics, give a short summary and put the full data in nearby text.
Decorative images that add nothing, like divider lines or background flourishes, should have empty alt text so screen readers skip them. Leave the attribute present but blank, rather than omitting it.
Common mistakes
Leaving the filename as alt text, such as IMG_2231.jpg, or repeating the same phrase on every image. Writing paragraphs. Placing important text only inside images. Describing stock photos as if they were your own work, which can mislead. Using the title field instead of alt.
Also avoid alt text that contradicts the visible caption. If a caption already describes the photo fully, a brief alt is enough.
How to add and audit it
In WordPress, open the media library and fill the Alternative Text field. Builders usually show a similar box in the image settings. For a hand-coded site, add the alt attribute in the image tag.
To audit, use a browser extension or crawler that lists images missing alt text, then work through the most important pages first. Make adding alt text part of your upload routine so you never build a backlog.
A before-and-after example
Weak: photo.jpg, or plumber cheap plumber near me emergency plumber. Better: Plumber checking a copper pipe under a kitchen sink. The first tells a screen reader user nothing and looks like stuffing. The second tells them what is happening and still gives context for search engines.
If you manage a large media library, prioritize in this order: images on service pages, then the home page, then blog posts, then old archives. A steady habit beats a one-time cleanup.
Treat the text as part of the content, not an afterthought. When writing a service page, decide what the photos are meant to show, and let that guide both the picture you pick and the sentence that describes it.
Common questions
Does alt text help SEO?
It gives search engines context, especially for image search, but it is mainly an accessibility feature.
Do I need alt text on every image?
Every image needs the attribute. Meaningful images need a description; decorative ones should be empty.
Should I put my city in alt text?
Only if the location is part of what the image shows. Avoid repeating it on every image.
This guide is general information. Search engines change how they work and their guidelines; check Google's current documentation for your situation. Nobody can guarantee a ranking.