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22-3376 Web Design 2 // Columbia College Chicago
REVIEW / WEB IMAGES
Applying Styles
The Cascade Inheritance Specificity
The “cascade” part of CSS is a set of rules for resolving conflicts with multiple CSS rules applied to the same elements. For example, if there are two rules defining the color or your h1 elements, the rule that comes last in the cascade order will “trump” the other.
The Cascade
Client (user) stylesheet
Linked (external) stylesheet
Embedded (internal) stylesheet
Inline (internal) Styles
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As a designer, your goal is to set an overall global consistent style, then add in more specific styles as needed. You can control how and where your styles are applied to your HTML by managing their inheritance and specificity.
Inheritance & Specificity
Most elements will inherit many style properties from their parent elements by default. A parent is a containing element of a child. HTML!<body> <div> <ul> <li></li> </ul> </div> </body>
relationship!parent of site!parent of ul and li, child of body!parent of li, child of div and body!child of ul, div, and body!!
Inheritance
bodymake the paragraph 16px, Verdana, red
pmake the paragraph blue
16px, Verdana, blue
Inheritance
Not all properties are inherited
Tutorial !
1-inheritance-specificity
Tutorial !
2-two-col-centered / float
Tutorial !
2-two-col-centered / bootstrap
Images can be integrated into your site as html <img> elements or pulled in
from your css.
How are images being used in the following sites? Images on the Web
Images can be integrated into your site as html <img> elements or pulled in
from your css.
How are images being used in the following sites?
Beyond the technical considerations, how do images create or influence the
experience?
!
What are the considerations you take into account before using an image in
your designs?
Rules for using web images
1 Save images in the right format
2 Save images at the right size
3 Measure images in pixels
What is the “right size”?
With the growing use of responsive design techniques and faster connections, it is becoming less crucial for designers to have their images perfectly sized to their box. The basic guideline is to have (just) enough pixels for your images to look great, however you are using them.
Image Formats
Screen image formats
Print image formats
jpg
jpgs are for images, like photographs, that have a lot of colors and gradations. It uses “lossy” compression, meaning that you can reduce the size of the image by reducing the quality of the image detail.
colors transparency?
24-bit:millions no
What is image detail?
Image quality is detail; the quality of the original capture can be accessed by how much actual live detail was recorded, pixel-by-pixel. The more you compress your jpgs, the more of these pixel-by-pixel details you making the same (blowing out). The result of too much compression is jpg artifacts and posterization.
GIGO
Tutorial !
3- images, Save for Web
png-24
There are two kinds of png images: 24-bit (png-24) and 8-bit (png-8). png-24 is a great format because it supports alpha transparency, which allows you to have images with transparent shadows, anti-aliasing, etc, and color underneath will show through.
There is no support for png-24 in ie6 (there is a workaround).
colors transparency?
24-bit:millions
yes(alpha transparency)
png-24: alpha transparency
png-8
png-8 is an 8-bit image format, meaning that it supports up to 256 colors. It supports binary transparency, meaning that pixels are either on or off – they have no transparency. This translates to jaggy edges (which you have to then plan for and work around).
You can reduce the color index (aka color table) to contain only the colors you need, resulting in very small image sizes. gif files are saved in “index” color mode.
colors transparency?
8-bit:256 colors
yes(binary transparency)
Should I use png or jpg?
For photos, you almost always go with jpg, because pngs will usually be much larger.
For icons, backgrounds, tiles, etc, that need transparency, use png-24.
Tutorial !
3- images, png-24
gif
gif if the workhorse for icons and vector graphics (like logos) that don’t need alpha transparency. Like png-8, it uses binary transparency. You can reduce the color index (aka color table) to contain only the colors you need, resulting in very small image sizes. gif files are saved in “index” color mode.
colors transparency?
8-bit:256 colors
yes(binary transparency)
Tutorial !
3- images, png-24
Tutorial !
4-bootstrap !
image techniques: background images, sprites, tiled backgrounds
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