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Chapter 3
Adding Images in HTML
Agenda• Understanding Web Page Images • Prepare Your Images for the Web • Insert an Image • Specify an Image Size • Add Alternative Text • Create an Image Label • Add Copyright Text to Images • Align an Image Horizontally • Align an Image Vertically • Center an Image • Wrap Text Between Images • Stop Text Wrap • Set an Image Border • Add Space Around an Image • Add a Background Image • Create an Image Banner
Understanding Web Page Images
• You can currently use only three image file formats on the Web: GIF, JPG, and PNG– A new format, SVG, is not yet in common use
• These formats all compress images to create smaller files– Knowing which file format to use for which type of image
is important
• If you choose the wrong file type, your image won’t compress or display properly
GIF (Graphics Interchange Format)• GIF uses a lossless compression technique,
meaning that no color information is discarded when the image is compressed
• The color depth of GIF is 8-bit, allowing a palette of no more than 256 colors
• GIF excels at compressing and displaying flat color areas, making it the logical choice for line art and color graphics
GIF Transparency• With GIF files, you can choose any one color in an
image to appear as transparent in the browser• The background color or pattern will show
through the areas that you have designated as transparent
• Using transparent areas allows you to create graphics that appear to have an irregular outside shape, rather than being bounded by a rectangle
Transparent and nontransparent GIFs
GIF Animation
• The GIF format lets you store multiple images and timing information about the images in a single file
• This means that you can build animations consisting of multiple static images that play continuously, creating the illusion of motion
JPG or JPEG (Joint Photographic Experts Group)
• JPG is best for photographs or continuous tone images
• JPGs are 24-bit RGB images that allow millions of colors
• JPGs use a “lossy” compression routine especially designed for photographic images– When the image is compressed, some color
information is discarded, resulting in a loss of quality from the original image
JPG (continued) • When you create the JPG file, you can also
manually balance the amount of compression versus the resulting image quality
• The higher the compression, the lower the image quality– You can play with this setting to create files that are as
small as possible but still look good
• Many photos can sustain quite a bit of compression while still maintaining image integrity
PNG (Portable Network Graphics)
• A royalty-free file format that is intended to replace GIF
• This lossless format compresses 8-bit images to smaller file sizes than GIF
• PNG supports transparency and interlacing but not animation
SVG (Scalable vector graphics)
• A new standard from the W3C• A language for describing two-dimensional
graphics using XML• SVG graphics are scalable to different display
resolutions and are printable• Not yet supported by most browsers
Insert an Image • The <img> tag defines an image in an HTML
page.• The <img> tag has two required attributes: src
and alt.• Note: Images are not technically inserted into
an HTML page, images are linked to HTML pages. The <img> tag creates a holding space for the referenced image.
• Tip: To link an image to another document, simply nest the <img> tag inside <a> tags.
Image Attributes and ValuesAttribute Value Description
align
topbottommiddleleftright
Specifies the alignment of an image according to surrounding elements
alt text Specifies an alternate text for an image
border pixels Specifies the width of the border around an image
height pixels Specifies the height of an image
hspace pixels Specifies the whitespace on left and right side of an image
src URL Specifies the URL of an image
vspace pixels Specifies the whitespace on top and bottom of an image
width pixels Specifies the width of an image
title text Specifies a LABEL for an image
<img src="balloons_sm.jpg" width="200" height="267" alt="Hot Air Balloon image" border="0" title="Up, up and away in a hot air balloon"/>
Example of Image tag
Add Copyright Text to Images
• Type © to create the copyright symbol.<IMG src=“image1.jpg”><br>© 2013 Khawarizmi College , All rights reserved.
• In this example, a line break tag• (<BR>) puts the copyright text on a new line.• The copyright text appears in the browser
window.
Center an Image • Click before the <IMG> tag and• type <DIV>.• Click inside the <DIV> tag and type
ALIGN=”center”.• Click after the closing bracket of• the <IMG> tag and type </DIV>.• The image appears centered on the Web page.Example<div align=“center”> <img src=“img1.jpg></div>
Stop Text Wrap • Click where you want to end thetext wrap and type <BR CLEAR=”?”>, replacing ? With the margin you want to clear, either left, right, or all.• The text wrapping ends at the selected point
on the page.• In this example, the next• paragraph starts on a different• line from the images.
Add a Background Image
Click inside the <BODY> tag and type BACKGROUND=”?”, replacing ? with the path to the image file you want to use.The Web browser displays the image as the page background.Example: <body background=“image1.jpg”>
Create an Image Banner
• At the top of the page, before any body text, type <IMG SRC=”?”>, replacing ? with the path to the banner file you want to use.
• Type WIDTH=”? ” within the <IMG> tag, replacing ? with a value in pixels.
• Type HEIGHT=”? ” within the <IMG> tag, replacing ? with a value in pixels.
• The Web browser displays the image as a banner at the top of the page.
• Example: <img src=“img1.gif” width=“468” height=“60”><BR>
Lab3Write a code in HTML to achieve the following tasks:• Insert an Image • Specify an Image Size • Add Alternative Text • Create an Image Label • Add Copyright Text to Images • Align an Image Horizontally • Align an Image Vertically • Center an Image • Wrap Text Between Images • Stop Text Wrap • Set an Image Border • Add Space Around an Image • Add a Background Image • Create an Image Banner