1. CIS 228
The Internet
1/13/11
Images

2. URL's Uniform Resource Locator
protocol://domain:port/path#fragment
Protocol – a scheme for exchanging information
http (hypertext transfer protocol), ftp, etc.
Domain – identifies a server
Port – optional number for the protocol to use
Path – specifies a file on the server
Fragment – specifies a location within the file

3. Domain Names Top level: com, org, net, edu, mil, …
Second level: google.com, cuny.edu, …
You can acquire these
Provided by Domain Name Registrars ($10/year)
Go Daddy, eNom, Tucows, Melbourne IT, Key-Systems
Deeper level: lehman.cuny.edu
Administered by the second level name owner
Typically, the first name identifies a machine
media.lehman.cuny.edu

4. The Image Element
An inline element that identifies an image to display
Tag: <img> (an empty element, no closing tag)
src attribute, where to find the image
Relative path to a local file, or
Uniform Resource Locator
alt attribute, text to display when src can't be found
width attribute, coveys size information to the browser
height attribute, also resizes the image
Use width (and height) to inform the browser
Not to resize an image

5. Image Processing Software
Adobe Photoshop – the gold standard
GIMP – open source Photoshop replacement
Image Converter – change image file format
Pixlr – web based image processor
Splashup – web based image processor

6. Common Image Formats jpg gif (depricated ??) png psd
Variable, lossy data compression
Good for photos (lots of colors)
gif (depricated ??)
Good for logos (small number or colors)
Transparency
png
Newer format with transparency (replacing gif ?)
psd
Proprietary, Adobe Photoshop format