About Graphics on Web

Graphics

Good design is clear thinking made visible. Good diagrams and interesting illustrations are visually arresting

and create documents that are distinct and memorable.

The Role of Web Graphics

Graphics as a Content Illustrations: Graphics can show you things, bringing pieces of the

world into your document Diagrams: Quantitative graphics and process diagrams can explain

concepts visually Quantitative data: Numeric charts can help explain financial,

scientific, or other data Analysis and causality: Graphics can help take apart a topic or show

what caused it Integration: Graphics can combine words, numbers, and images in a

comprehensive explanation

Characteristics of Web Graphics

Color displays Screen Resolution Gamma Graphics and bandwidth

Graphic File Formats The primary web file formats are GIF (pronounced “jiff”), JPEG (“jay-peg”), and,

to a much lesser extent, PNG (“ping”) files. GIF Graphics JPEG Graphics PNG Graphics

GIF Graphics

Many images on the web are in GIF format, and virtually all web browsers that support graphics can display GIF files. GIF files are 8-bit graphics and thus can only accommodate 256 colors.

GIF file compression

GIF Graphics

Dithering : GIF images can contain no more than 256 colors. The process of reducing many colors to 256 or fewer is called dithering.

Improving GIF compression

Interlaced GIF Transparent GIF

Advantages of GIF files

GIF is the most widely supported graphics format on the web GIFs of diagrammatic images look better than JPEGs GIF supports transparency and interlacing

JPEG Graphics JPEG images are full-color images that dedicate at least 24 bits of memory to each pixel,

resulting in images that can incorporate 16.8 million colors. JPEG images are used extensively among photographers, artists, graphic designers, medical imaging specialists, art historians, and other groups for whom image quality and color fidelity is important.

Advantages of JPEG images

JPEG achieves huge compression ratios, which mean faster downloads

JPEG produces excellent results for most photographs and complex images

JPEG supports full-color (24-bit, true-color) images

PNG Graphics

PNG is an image format developed by a consortium of graphic software developers as a nonproprietary alternative to the GIF image format.

PNG graphics were designed specifically for use on web pages, and they offer a range of attractive features, including a full range of color depths, support for sophisticated image transparency, better interlacing, and automatic corrections for display monitor gamma.

PNG supports full-color images and can be used for photographic images

Imaging Strategies

Photographs as GIFs

Imaging Strategies

Photograph as JPEGs

Graphics Markup Height and width tags : Graphic source tags tell the browser how much space to devote

to a graphic on a page, and they instruct the browser to lay out your web page even before the graphics files have begun to download.

Alt text: HTML has several built-in fallbacks designed to allow web pages to work under different conditions. One of these is the “alt” attribute of the <img>tag. The alt attribute allows us to supply an alternate text description with any images we place on our page.

Colored Backgrounds: Web colors offer a zero-bandwidth means to change the look of your pages without adding graphics. They also allow you to increase the legibility of your pages, tune the background color to complement foreground art, and signal a broad change in context from one part of your site to another. 

Background colors and legibility: A primary factor affecting legibility is the contrast between text and background. Low-contrast type diminishes the reader’s ability to differentiate between the color of the background and the text, which in turn makes it difficult to distinguish letterforms

Graphics Markup

Background Graphics : Cascading Style Sheets offer powerful tools for designing layouts that include background graphics. With css, you can set a background graphic and define where it displays, whether it repeats, and, if so, in what direction, whether the image is fixed in place or scrolls with the page, and more. Background graphics can be attached to the entire page or to individual elements, such as the banner, navigation, or content area

Conclusion

Thus, graphics makes our website look more beautiful and attractive.