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The “border” attribute is obsolete. Consider specifying “img { border: 0; }” in CSS instead.
<img> tags no longer accept a border attribute. This can be defined using CSS instead, for example:
<img src="..." alt="..." style="border:0;" />Related W3C validator issues
<img> tags, used to include images on a document, require an alt attribute to describe the contents of the image. This is essential for users that cannot see the image (like screen reader users), or as an alternate text when the image cannot be displayed. Example:
<img src="photo.jpg" alt="Person holding a cat" />
The <table> element does not accept a height attribute. Use CSS instead.
A start tag for <img> has been found inside a <noscript> section within the <head>, where it’s not allowed. Consider moving it to the <body> section.
The HTML <noscript> element defines a section of HTML to be inserted if a script type on the page is unsupported or if scripting is currently turned off in the browser.
When JavaScript is disabled, the content inside <noscript> will be used instead, so this content must fit within its parent section. As an <img> tag is not allowed inside <head>, this will raise an issue. Instead, consider moving the <noscript> part to the <body> section.
This issue is often related to 3rd party tracking pixels like the Facebook or LinkedIn conversion tracking pixels. For example, the Facebook pixel instructions tell you to insert it like this:
<html>
<head>
<script>
...some script...
</script>
<noscript>
<img src="..." />
</noscript>
</head>
<body>
...
</body>
</html>
Instead, consider moving the <noscript> part inside the <body>, where the <img> makes sense to be inserted:
<html>
<head>
<script>
...some script...
</script>
</head>
<body>
...
<noscript>
<img src="..." />
</noscript>
</body>
</html>
Learn more:
The src attribute for <img> tags is required, to define the source of the image, like in this example:
<img src="photo.jpg" alt="wombat" />
Space characters are not allowed in src attributes. Instead, they should be converted to %20. In this example, the first line is invalid and the second is valid:
<img src="https://example.com/?s=some term" alt="description" />
<img src="https://example.com/?s=some%20term" alt="description" />
The src attribute on an <img> tag is not allowed to contain space characters. You should replace them with “%20“.
<img> elements accept a width attribute to specify the size in pixels. This value can only be an integer, it should not contain units or %. If you need to specify a percentage width, you can do that with CSS:
<img src="photo.jpg" alt="red car" style="width:100%;">
The width attribute on <img> elements expects a digit to indicate the number of pixels. Ensure that this attribute contains only digits.
For example:
<!-- This is invalid because width is not a digit -->
<img width="225px" alt="cat" src="cat.jpg" />
<!-- This is valid -->
<img width="225" alt="cat" src="cat.jpg" />
A CSS definition for background-image could not be understood by the parser. Check its definition to ensure that it’s well formed and that it contains an appropriate value.
The specified CSS filter is not a standard one, and may only work in some browsers.
Check out the Filter Effects W3C Working Draft
Padding properties, unline margin properties, don’t accept negative values. Read more about the CSS box model
CSS styles could not be parsed, check the indicated line to find what caused the parser to fail. Common causes are unclosed curly brackets or comments, missing semicolons or unexpected or empty properties.
Read more about CSS: Cascading Style Sheets syntax
A CSS definition for an X property could not be understood by the parser. Check it to ensure that it’s well formed and that it contains an appropriate value.
<img> tags used to display images require the attribute src to indicate the source of the image, for example <img src="/img/photo.jpg" />.
<td> elements no longer accept an align attribute. This can be achieved using CSS like this:
<td style="text-align:center;">content</td>
The <center> tag is no longer valid in HTML, you should use CSS instead, for example:
<p style="text-align:center">this text will be centered</p>
The <font> element, used to define the font face, size and color in previous versions of HTML, is no longer valid in HTML5. Instead, you should rely on CSS styles.
For example, you can define a font size of 12px, bold text with inline styles like this:
<p style="font-size: 12px; font-weight: bold;">some text</p>
Learn more about CSS fonts:
A single <img> element is used to embed an image, so adding the img role to it is redundant.
The ARIA img role can be used to identify multiple elements inside page content that should be considered as a single image. These elements could be images, code snippets, text, emojis, or other content that can be combined to deliver information in a visual manner, for example:
<div role="img" aria-label="Description of the overall image">
<img src="graphic1.png" alt="">
<img src="graphic2.png">
</div>
Learn more:
<td> elements no longer accept a valign attribute. This can be achieved using CSS like this:
<td style="vertical-align:middle;">content</td>
Both <table> and <td> elements no longer accept a width attribute. Instead, you should use CSS as in this example:
<table style="width:100%;">
<tr>
<td style="width:50px;">Name</td>
</tr>
</table>
You’re using an attribute X that is no longer valid for element Y, but you can use CSS to achieve the same effect.
Check the HTMLImageElement.srcset guide to learn about the correct usage of the srcset and sizes attributes.
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