Writing effective alt text is a critical, yet often overlooked, component of both on-page SEO and web accessibility. This small snippet of descriptive text, added to an image’s HTML code, serves a powerful dual purpose. It provides context to search engines and makes web content accessible to visually impaired users. However, a surprising number of websites make fatal mistakes with their alt text, harming their ranking potential and excluding a significant portion of their audience. This guide exposes thirty of the most common and costly alt text errors and provides the correct way to write it for SEO success.
Many marketers and content creators treat alt text as an afterthought, a minor box to be checked on their content publishing checklist. This is a significant strategic error. In a world where visual content and image search are increasingly important, optimizing every image is non-negotiable. By understanding and avoiding the common pitfalls, professionals can transform their alt text from a missed opportunity into a powerful asset. The following sections will provide a deep dive into these critical mistakes and offer a clear framework for getting this essential element right every time.
The Dual Purpose of Alt Text: SEO and Accessibility
Before exploring the specific mistakes, it is crucial to have a firm grasp of the two primary and equally important functions of alt text. A failure to understand this dual purpose is the root cause of most optimization errors.
A Critical Signal for Search Engines
Search engine crawlers cannot “see” an image in the same way a human can. They rely on the textual information associated with the image to understand its content and context. Alt text is the primary source of this information. A well-written, descriptive alt text helps search engines to understand what an image is about. This contributes to the overall topical relevance of the page and is a crucial part of a comprehensive image seo strategy. It can also help the image itself to rank in image search results, creating another valuable stream of organic traffic.
An Essential Tool for Accessibility
The primary purpose for which alt text was created is web accessibility. It is a fundamental principle of inclusive web design. Visually impaired users who rely on screen reader software cannot see the images on a page. The screen reader reads the alt text aloud, describing the image to the user. Without descriptive alt text, these users are missing out on a significant part of the content and experience. Writing good alt text is therefore an ethical and often legal requirement for creating an accessible website.
30 Fatal Alt Text Mistakes That Kill Your Rankings
Getting alt text right is a matter of avoiding a series of common but easily correctable errors. The following list details thirty of the most fatal mistakes and provides the clear, correct approach for each one.
#1: Leaving Alt Text Completely Empty
This is the most common and most damaging mistake. Leaving the alt attribute empty for an important image means that both search engines and screen reader users get no information about it.
#2: Using “Image of…” or “Picture of…”
The alt text is already associated with an image tag, so screen readers will announce it as an image. Starting the description with “image of” or “picture of” is redundant and creates a clunky user experience.
#3: Stuffing Alt Text with Keywords
This is an outdated and spammy tactic. Stuffing the alt text with a long list of keywords is a clear red flag to search engines and provides a terrible experience for screen reader users.
#4: Using the Same Alt Text for Every Image
Every image on a page should have its own unique alt text that accurately describes that specific image. Using the same generic alt text for all images is a missed opportunity for relevance.
#5: Writing Vague or Unhelpful Descriptions
Alt text like “dog” is not helpful. A much better description would be “golden retriever puppy chasing a red ball on a green lawn.” Be specific and descriptive.
#6: Not Describing the Important Details
The description should focus on the most important and relevant details of the image. For a product photo, this might include the color, model, and key features.
#7: Ignoring the Context of the Surrounding Text
Good alt text should make sense in the context of the page’s content. It should complement the surrounding text and contribute to the overall topic of the page.
#8: Forgetting the Purpose of the Image
Consider why the image is there. Is it to illustrate a specific step in a tutorial? Is it to show the final product of a recipe? The alt text should reflect this purpose.
#9: Describing a Decorative Image
If an image is purely decorative and provides no informational value (e.g., a background pattern or a stylistic border), it should have an empty alt attribute (alt=""). This tells screen readers to skip it.
#10: Writing Alt Text That is Too Long
Alt text should be concise. While it needs to be descriptive, it should not be a long paragraph. Aim for a descriptive but brief phrase or sentence.
#11: Not Including Text That is Part of the Image
If an image contains important text, such as a headline on a promotional banner or a label on a chart, that text must be included in the alt text.
#12: Using Only the Primary Keyword
While it is good to include a keyword if it is natural, the alt text should not be just the keyword. It must be a descriptive phrase that makes sense to a human reader.
#13: Confusing Alt Text with the Image Title
The alt attribute and the title attribute are different. The title attribute provides additional information that appears as a tooltip when a user hovers over the image. The alt attribute is for accessibility and SEO. The alt text is the one that is truly essential.
#14: Confusing Alt Text with the Image Caption
A caption is the text that is visibly displayed on the page below an image. While both can provide context, the alt text is hidden in the code and is specifically for screen readers and search engines.
#15: Relying on Auto-Generated Alt Text
Many content management systems automatically generate alt text from the image file name. This is often not descriptive or user-friendly and should always be manually reviewed and edited.
#16: Hardcoding Alt Text into the HTML Incorrectly
A simple typo in the HTML code, such as writing alt-text= instead of alt=, can cause the alt text to not be recognized. It is important to use the correct syntax.
#17: Forgetting Alt Text for Linked Images
If an image is used as a link, the alt text serves the function of the anchor text. It should describe the destination of the link. For example, a company logo in the header that links to the homepage should have an alt text of “Company Name Homepage.”
#18: Not Auditing for Missing Alt Text
It is a crucial task to periodically run a site crawl to find all the images on a website that are missing alt text. This is a standard item on any professional on page seo checklist.
#19: Neglecting Alt Text on E-commerce Product Images
For e-commerce sites, every product image should have detailed alt text. This should include the product name, model number, color, and any other key identifying features. This is critical for both accessibility and image search performance.
#20: Forgetting Alt Text for Infographics
Infographics can contain a large amount of valuable information. The alt text for an infographic should provide a concise summary of the main topic and the key data points presented in the graphic.
#21: Not Optimizing for Both SEO and Accessibility
The best alt text finds the perfect balance between being descriptive for accessibility and being relevant for SEO. The two goals are not mutually exclusive; they are complementary.
#22: Using Punctuation Incorrectly
Screen readers interpret punctuation. A properly punctuated sentence in the alt text will be read more naturally than a simple string of words.
#23: Not Using a Consistent Style
For a large website, it is a good practice to establish a consistent style and format for alt text. This creates a more predictable experience for users and makes the optimization process more efficient.
#24: Ignoring Alt Text in Your Content Workflow
Alt text should not be an afterthought. It should be a required field in the content creation and publishing workflow. This ensures that it is never forgotten.
#25: Thinking Alt Text is a “Low Priority” Task
Given its dual impact on SEO and accessibility, optimizing alt text is a high-impact, low-effort task. Treating it as a low priority is a significant mistake that leaves value on the table. It’s a key part of building a seo friendly website.
#26: Not Considering Image Search Intent
When writing alt text, consider what a user might be searching for when they are looking for that image. Aligning the alt text with potential image search queries can improve its visibility.
#27: Writing Alt Text that Contradicts the Page Content
The alt text for an image should be consistent with the main topic of the page on which it appears. A mismatch can be a confusing signal to both users and search engines.
#28: Forgetting About File Names
The image file name is another important signal of its content. A descriptive file name (e.g., blue-suede-shoes.jpg) complements a descriptive alt text. A generic file name (e.g., IMG_1234.jpg) is a missed opportunity.
#29: Not Updating Alt Text When an Image is Changed
If an image on a page is updated or replaced, the alt text must also be updated to accurately reflect the new image.
#30: Viewing Alt Text as a Chore, Not an Opportunity
The biggest mistake of all is viewing alt text as a tedious chore. Instead, it should be seen as a valuable opportunity: an opportunity to improve rankings, an opportunity to attract traffic from image search, and an opportunity to create a more inclusive experience for all users. It is a fundamental part of good on page seo.
A Summary Checklist: Avoiding the 30 Mistakes
To help internalize these best practices, here is a concise summary of the thirty mistakes to avoid.
The Ultimate “Don’t Do This” List
- Don’t leave alt text empty.
- Don’t use “image of” or “picture of.”
- Don’t stuff it with keywords.
- Don’t use the same alt text for every image.
- Don’t be vague. Be specific and descriptive.
- Don’t forget important details.
- Don’t ignore the surrounding context.
- Don’t forget the image’s purpose.
- Don’t describe purely decorative images.
- Don’t make it too long.
- Don’t forget to include text within the image.
- Don’t use only the keyword.
- Don’t confuse it with the image title.
- Don’t confuse it with the caption.
- Don’t rely on auto-generated text.
- Don’t use incorrect HTML syntax.
- Don’t forget it for linked images.
- Don’t forget to audit for missing alt text.
- Don’t neglect it on product images.
- Don’t forget it for infographics.
- Don’t optimize for only SEO or only accessibility.
- Don’t forget proper punctuation.
- Don’t be inconsistent in your style.
- Don’t ignore it in your workflow.
- Don’t treat it as a low priority.
- Don’t ignore image search intent.
- Don’t let it contradict the page content.
- Don’t forget to use descriptive file names.
- Don’t forget to update it when an image changes.
- Don’t view it as a chore.
A Small Detail with a Massive Impact
Writing high-quality alt text is a simple but profoundly important practice. It is a task that sits at the perfect intersection of technical SEO, content relevance, and inclusive user experience. By systematically avoiding the thirty fatal mistakes outlined in this guide, webmasters and content creators can unlock significant benefits. They can improve their page’s relevance, earn more traffic from image search, and create a more welcoming and accessible experience for all users. In the world of on-page optimization, mastering the small detail of alt text can have a massive and lasting impact.
Frequently Asked Questions About Alt Text
What is alt text?
Alt text, or alternative text, is a written description of an image that is added to a website’s HTML code. It is read aloud by screen readers for visually impaired users and is used by search engines to understand the content of the image.
How do you write good alt text?
Good alt text is descriptive, concise, and relevant. It should accurately describe the image in the context of the page. If it is natural to do so, it can also include the page’s target keyword.
Is alt text a ranking factor?
Yes, alt text is a ranking factor. It helps search engines to understand the images on a page, which contributes to the page’s overall topical relevance. It is also the primary factor for ranking in image search.
How long should alt text be?
Alt text should be concise. A good rule of thumb is to keep it to a reasonable length, similar to a short sentence.
What is the difference between alt text and an image title?
Alt text is for accessibility and SEO; it describes the image for screen readers and search engines. An image title is an attribute that provides extra information and typically appears as a tooltip when a user hovers over the image. Alt text is far more important. For more general advice, you can review some popular seo tips.