(Shelly Cashman Series) Gary B. Shelly, H. Albert Napier, Ollie N. Rivers-Web design_ introductory concepts and techniques -Cengage Learning (2008)
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142 Chapter 5 Typography <strong>and</strong> Images<br />
If limitations of time, available resources, or expertise prohibit you from creating<br />
your own images, various sources for already created graphics files are readily available.<br />
Digitized images can be purchased on CD/DVD or from an online store. WYSIWYG<br />
editors, image editing software, or illustration software often provide sample images or<br />
drawing templates. You might also be able to download images offered for a fee at some<br />
<strong>Web</strong> sites or download public domain images, such as those found at many U.S. government<br />
<strong>Web</strong> sites. Take care to ensure that you are not violating copyright restrictions when<br />
you download images from the <strong>Web</strong>.<br />
DESIGN<br />
TIP<br />
Before downloading photos or illustrations from the <strong>Web</strong>, ensure that you are<br />
not violating copyright restrictions or incurring royalty or licensing fees for the<br />
images’ use.<br />
Additionally, you should carefully read the Terms <strong>and</strong> Conditions for Use statement<br />
before you download images. You might be required to provide a back link to the page<br />
that offers the image, or you might be asked to add a credit line for photographs, even<br />
those in the public domain.<br />
Image File Formats<br />
Image files are grouped into two categories: raster <strong>and</strong> vector. Raster images, also called<br />
bitmaps, are created pixel by pixel. Figure 5-12 illustrates a bitmap image of sunflowers<br />
zoomed to see the individual pixels in the image. Bitmaps can be created <strong>and</strong> edited in<br />
image editing software, such as Microsoft Paint ® (installed with the Windows operating<br />
system), Adobe Photoshop CS3, <strong>and</strong> Corel Paint Shop Pro.<br />
A bitmap contains a specific number of pixels measured as pixels per inch (ppi) <strong>and</strong> is<br />
resolution dependent, meaning it cannot be resized in image editing software without<br />
losing some image quality. A file extension — a period (.) <strong>and</strong> a file format identifier — is<br />
added to a file’s name when the file is saved electronically. Bitmap files are commonly referenced<br />
by their file extensions, such as GIF or JPEG, as shown in Figure 5-13. You can<br />
save an image created originally in one bitmap format in another bitmap format using the<br />
Save As comm<strong>and</strong> in your image editing software.<br />
Figure 5-12 Individual pixels are visible in a zoomed bitmap image.
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