HTML Images

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Images can improve the design and the appearance of a web page

Example

<!DOCTYPE html>
<html>
<body>

<h2>HTML Image</h2>
<img src=”pic_trulli.jpg” alt=”Trulli” width=”500″ height=”333″>

</body>
</html>

Example

<!DOCTYPE html>
<html>
<body>

<h2>HTML Image</h2>
<img src=”img_girl.jpg” alt=”Girl in a jacket” width=”500″ height=”600″>

</body>
</html>

Example

<!DOCTYPE html>
<html>
<body>

<h2>HTML Image</h2>
<img src=”img_chania.jpg” alt=”Flowers in Chania” width=”460″ height=”345″>

</body>
</html>

HTML Images Syntax

The HTML <img> tag is used to embed an image in a web page.

Images are not technically inserted into a web page; images are linked to web pages. The <img> tag creates a holding space for the referenced image.

The <img> tag is empty, it contains attributes only, and does not have a closing tag.

The <img> tag has two required attributes:

src – Specifies the path to the image
alt – Specifies an alternate text for the image

Syntax

The src Attribute

The required src attribute specifies the path (URL) to the image.

Note: When a web page loads, it is the browser, at that moment, that gets the image from a web server and inserts it into the page. Therefore, make sure that the image actually stays in the same spot in relation to the web page, otherwise your visitors will get a broken link icon. The broken link icon and the alt text are shown if the browser cannot find the image.

Example

<!DOCTYPE html>
<html>
<body>

<h2>Alternative text</h2>

<p>The alt attribute should reflect the image content, so users who cannot see the image get an understanding of what the image contains:</p>

</body>
</html>

The alt Attribute

The required alt attribute provides an alternate text for an image, if the user for some reason cannot view it (because of slow connection, an error in the src attribute, or if the user uses a screen reader).

The value of the alt attribute should describe the image:

Example

<!DOCTYPE html>
<html>
<body>

<h2>Alternative text</h2>

<p>The alt attribute should reflect the image content, so users who cannot see the image get an understanding of what the image contains:</p>

</body>
</html>

If a browser cannot find an image, it will display the value of the alt attribute:

Example

<!DOCTYPE html>
<html>
<body>

<p>If a browser cannot find the image, it will display the alternate text:</p>

</body>
</html>

Image Size – Width and Height

You can use the style attribute to specify the width and height of an image.

Example

<!DOCTYPE html>
<html>
<body>

<h2>Image Size</h2>

<p>Here we use the style attribute to specify the width and height of an image:</p>

</body>
</html>

Alternatively, you can use the width and height attributes:

Example

<!DOCTYPE html>
<html>
<body>

<h2>Image Size</h2>

<p>Here we specify the width and height of an image with the width and height attributes:</p>

</body>
</html>

The width and height attributes always define the width and height of the image in pixels.

Width and Height, or Style?

The width, height, and style attributes are all valid in HTML.

However, we suggest using the style attribute. It prevents styles sheets from changing the size of images:

Example

<!DOCTYPE html>
<html>
<head>
<style>
/* This style sets the width of all images to 100%: */
img {
width: 100%;
}
</style>
</head>
<body>

<h2>Width/Height Attributes or Style?</h2>

<p>The first image uses the width attribute (set to 128 pixels), but the style in the head section overrides it, and sets the width to 100%.</p>

<p>The second image uses the style attribute to set the width to 128 pixels, this will not be overridden by the style in the head section:</p>

</body>
</html>

Images in Another Folder

If you have your images in a sub-folder, you must include the folder name in the src attribute:

Example

<!DOCTYPE html>
<html>
<body>

<h2>Images in Another Folder</h2>
<p>It is common to store images in a sub-folder. You must then include the folder name in the src attribute:</p>

</body>
</html>

Images on Another Server/Website

Some web sites point to an image on another server.

To point to an image on another server, you must specify an absolute (full) URL in the src attribute:

Example

<!DOCTYPE html>
<html>
<body>

<h2>Images on Another Server</h2>

</body>
</html>

Notes on external images: External images might be under copyright. If you do not get permission to use it, you may be in violation of copyright laws. In addition, you cannot control external images; they can suddenly be removed or changed.

Animated Images

HTML allows animated GIFs:

Example

<!DOCTYPE html>
<html>
<body>

<h2>Animated Images</h2>

<p>HTML allows moving images:</p>

</body>
</html>

Image as a Link

To use an image as a link, put the <img> tag inside the <a> tag:

Example

<!DOCTYPE html>
<html>
<body>

<h2>Image as a Link</h2>

<p>The image is a link. You can click on it.</p>

</body>
</html>

Image Floating

Use the CSS float property to let the image float to the right or to the left of a text:

Example

<!DOCTYPE html>
<html>
<body>

<h2>Floating Images</h2>
<p><strong>Float the image to the right:</strong></p>

<p>
<img src=”smiley.gif” alt=”Smiley face” style=”float:right;width:42px;height:42px;”>
A paragraph with a floating image. A paragraph with a floating image. A paragraph with a floating image.
</p>

<p><strong>Float the image to the left:</strong></p>
<p>
<img src=”smiley.gif” alt=”Smiley face” style=”float:left;width:42px;height:42px;”>
A paragraph with a floating image. A paragraph with a floating image. A paragraph with a floating image.
</p>

</body>
</html>

Common Image Formats

Here are the most common image file types, which are supported in all browsers (Chrome, Edge, Firefox, Safari, Opera):

Abbreviation File Format File Extension

APNG	Animated Portable Network Graphics	.apng
GIF	Graphics Interchange Format	.gif
ICO	Microsoft Icon	.ico, .cur
JPEG	Joint Photographic Expert Group image	.jpg, .jpeg, .jfif, .pjpeg, .pjp
PNG	Portable Network Graphics	.png
SVG	Scalable Vector Graphics	.svg

Chapter Summary

Use the HTML <img> element to define an image
Use the HTML src attribute to define the URL of the image
Use the HTML alt attribute to define an alternate text for an image, if it cannot be displayed
Use the HTML width and height attributes or the CSS width and height properties to define the size of the image
Use the CSS float property to let the image float to the left or to the right

Note: Loading large images takes time, and can slow down your web page. Use images carefully.

HTML Exercises

Example

<!DOCTYPE html>
<html>
<body>

<h2>Floating Images</h2>
<p><strong>Float the image to the right:</strong></p>

</body>
</html>

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