Alt text is a short description of an image. It gives screen reader users the context of what's in a photo, graphic, or illustration. Without it, the screen reader will either skip the image or read the file name, for example, "image1.jpeg". The word “Image1.jpeg” tells the user nothing about what's actually there.\Developers and editors often struggle with knowing how to write alt text well. These are the most common mistakes and how to avoid them.Mistake 1: Starting with "image of" or "photo of"One of the most frequent alt text mistakes is beginning the description with "image of" or "photo of." If the element is in an tag or because role="img", screen readers will already announce that the element is an image. If an alt text begins with "image of," the user hears the word “image” twice: "Image. Image of a person in front of a computer."\Instead, start directly with the description. alt="Person in front of a computer" means the user hears "Image. Person in front of a computer", which is much clearer.\There is one exception to this rule. Headshot photos can start with "Headshot of Dr. Smith." Screen reader announcing, “Headshot” is both accepted and genuinely useful.Mistake 2: Forgetting images that contain textIf an image contains any text, for example, a quote card, a data graphic, or a banner, then that text needs to be in the alt text too. Screen readers can't read text that's embedded inside an image file. Without it, screen reader users lose access to information that sighted users can see plainly.\The alt text should repeat the text verbatim so that everyone gets the same information. For example, if a graphic reads "1 in 5 people has a learning or thinking difference," those exact words should appear in the alt text.Mistake 3: Descriptions that are too vagueAlt text is there to give screen reader users the context of an image. Being too vague defeats the purpose entirely. "A person doing something" tells the user nothing. What is the person doing? Studying? Riding a bike? Watching TV? The answer changes the meaning of the page.\Good alt text answers the question: why is this image here, and what does it show? If a photo shows a student taking notes in a classroom, say that. The specifics are what make the description useful. Imagine you were on a website and all of the images were blurred out, but had text over them. Wouldn’t you want the text to be descriptive?Mistake 4: Describing a functional image instead of its actionImages that link somewhere or trigger an action need a different approach. The alt text should describe what happens on click - not what the image looks like.\A magnifying glass icon is a common example. Describing it as a "magnifying glass" tells the user what the image looks like, but not what it does. The alt text should say "Search", because that's the action the user can take if they click on the button. This is especially important for icon buttons, linked images, and calls to action in emails. When an image does something, the alt text should tell the user what that something is.Mistake 5: Adding alt text to every image, including ones that don't need itNot every image needs alt text. Before writing anything, it helps to ask: if this image disappeared, what would be lost? If the answer is nothing - because the image is purely decorative, like a background pattern or a visual divider - the alt text field should be left blank. Adding descriptions to decorative images creates unnecessary clutter for screen reader users.\The same applies to images that repeat what the surrounding text already says. If a caption fully explains what's shown, writing it again in the alt text is redundant. When you're genuinely not sure, it's better to add alt text than to skip it.ConclusionAlt text is a small thing that makes a significant difference. For a screen reader user, it's often the only way to understand what an image is communicating - and when it's missing, wrong, or unhelpful, that user loses context that everyone else gets automatically.\The mistakes above are easy to fall into, especially under deadline pressure or when alt text feels like a final checkbox rather than part of the writing process. But treating it as part of the work - not an afterthought - is what moves the needle. A developer who understands why functional images need action-based descriptions, or an editor who knows not to start with "image of," writes better alt text consistently, not just when someone's checking.\It also helps to test with an actual screen reader occasionally. Reading alt text out loud - hearing "Image. Image of a person" - makes the problem concrete in a way that style guides can't always replicate. Small habits like that build a team culture where accessibility isn't an extra step, but the standard way things get done.\Alt text takes a couple of minutes to write well. For a screen reader user, those minutes are the difference between getting the full picture and being left out of it entirely.