Photos and illustrations bring vitality and "pop" to any body of text. To maximize the effectiveness of a graphic, it's important to use the correct file format. From .pdf and .eps to .bmp and .psd, the alphabet soup of file formats is confusing. Here's a glossary of the most frequently used formats.
Illustrations should be in a vector format, which is based on geometry. Vector images can be enlarged or reduced without compromising their quality. This is especially important when the finished size of an image is large, such as on a banner. Among the most frequently used vector formats are:
.eps = encapsulated postscript
.ai = created in Adobe Illustrator
.fh = created in Freehand
.wmf = Windows Metafile
.cdr = created in Corel Draw
Photographs are always in a raster format, also called a bitmapped format. This format is based on pixels, the tiny squares that comprise the image. When a photo is enlarged, the pixels become more evident, sometimes creating a jaggedy and fuzzy image. The major raster formats that can be used in word-processing and graphic applications are:
.jpg = joint photographic experts group (the geniuses/dorks who devised this format)
.psd = created in Adobe Photoshop
.bmp = bitmapped image
.png = portable network graphic, designed for internet and screen use
.gif = graphics interchange format, designed for internet and screen use, displays a limited number of colors
A .pdf is a portable document format, a hybrid specification designed by Adobe for sharing documents, images, etc. between different computer operating systems. It can contain both vector and raster computer language. A .pdf is similar to a snapshot, it's difficult to revise or edit without specialized software.
BTW, if you make soup with the letters from these formats, you'd use more than half the alphabet: ABCDEFGHIJMNPRSW.