Technology Freaks: Images, Audio, & Video

Users browse the internet in search of interesting and informational content, commonly found in the form of plain text. To accompany this plain text, HTML provides a way to give users rich media in the form of images, audio tracks, and videos.

The ability to include images, audio tracks, and videos within websites has been around for some time. Browser support for images has generally been pretty good, while audio and video support has left something to be desired. With the help of new technology, and the push of social media, more and more audio tracks and video clips have made their way online.

Today, we can freely use images, audio, and video knowing that support is widely accepted across all major browsers with the addition of HTML5 and the help of Flash alternatives.

Adding Images

To begin adding images to a page the img inline element is used. The img element is self containing, in that it doesn’t wrap any other content and exists as a single tag. For the img element to work, a src attribute value must be included to specify the source of the requested image. The src attribute value comes in way of a URL, most often relative to the server upon which the website is hosted.

In conjunction with the src attribute the alt attribute, known as alternative text, should be applied. The alt attribute value is displayed in place of the image should the image not be available. Also, the alt text is the cursor tooltip text that may be shown when hovering over the image.


<img src="cows.jpg" alt="Brown and white cows in a field">

Adding an Image Demo

Supported Image Formats

Images come in a variety of different file formats, and each browser may choose to support a given file format or not. By and large, the most commonly supported file formats online include bmp, gif, jpg, and png. Of these, the most widely used formats today include jpg and png. jpg formatted images offer a quality looking image with high color counts while still being able to scale the file size for faster load times. png formatted images are great for images with transparencies or low color counts.

Sizing Images

There are a couple of different ways to size images so that they work well on a page. One option is to use the heightand width attributes directly within the img tag in HTML. While this works, it also puts styles in the HTML. Since styles should specifically be reserved for CSS, let’s use the CSS height and width properties instead.

Specifying either a height or width will automatically adjust the other dimension to maintain the aspect ratio of the image. As an example, if I wanted an image to be 200 pixels tall, but didn't mind how wide it was, I could set the heightto 200px and the width of the image would automatically adjust accordingly. Setting both a height and width will work as well, however doing so may also break the aspect ratio of an image causing it to appear contorted.

Before getting too excited about resizing images with HTML or CSS it is worth noting that images should be resized to their desired height and width outside of the browser if possible. Taking a 1,000 pixel wide image and dropping it down to 100 pixels wide in the browser still means the original image, all 1,000 pixels, will need to be loaded and then scaled down. This is a less than ideal solution and can cause a large load time, especially on mobile devices.


img {
  height: 200px;
  width: 200px;
}

Sizing an Image Demo

Positioning Images

Images can be positioned in quite a few different ways, including inline, block, flush left, flush right, and so on. All of these positions are obtained using the CSS float property, along with other box model properties including margin,padding, border, and display.

Inline Positioning Images

The img element by default is an inline level element. Adding an image to a page without any styles will position that image directly in place while all the other content will fall inline with it as necessary, as seen below.


<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis  nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute <img src="images-audio-video/cows.jpg" alt="Brown and white cows in a grass field"> irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p>

Inline Positioning an Image Demo

Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute Brown and white cows in a grass field

irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Leaving images in their default positioning isn’t very common. Most often images are set to be displayed as block level elements or floated flush to one side. Using a small image inline with text should only be done when the image holds actual value to the page and has an appropriate alternative text. If an image, or icon, is used as part of the user interface or for decoration, it should be added to the page as a CSS background image.

Block Positioning Images

Adding the CSS property display and setting its value to block forces the image to be a block level element. Doing so makes the image appear on its own line, leaving the surrounding content to be positioned above and below the image.


img {
  display: block;
}

Block Positioning an Image Demo

Positioning Images Flush Left or Right

Sometimes displaying an image as inline or block isn’t the ideal usage. You may want the image to appear flush to the left or right while letting all of the other content surround the image as necessary. To do this the CSS float property is used with the value of either left or right.

Floating an image is a start, but all of the other content will align directly up against it. To provide an adequate amount of spacing around an image the margin property is used. Additionally, we can use the padding, border, andbackground properties to build a frame for the image if desired.


img {
  background: #e8eae9;
  border: 1px solid #c6c9cc;
  float: right;
  margin: 8px 0 0 20px;
  padding: 4px;
}

Floating & Framing an Image Demo

Mauris ut lectus quis mauris ornare iaculis a vel ligula. Quisque sed est sed arcu tincidunt aliquet. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Nam posuere accumsan mauris, nec lacinia risus pretium et. Suspendisse eget nisi facilisis nisl tristique consequat. Vivamus scelerisque accumsan vulputate. Sed bibendum felis id dui ornare tincidunt. Sed a pretium nisl.

Technology Freaks

Wednesday 28 August 2013

Images, Audio, & Video - Part 1