Common desktop publishing/web file formats are: JPG, PNG, GIF, TIFF, EPS, PDF, BMP, DOC, PUB, ZIP.
Of course, there are numerous others but these are used most often in a typical office environment. Here is a very basic overview of when to use each:
JPG--web graphics with continuous tones (i.e. photos), usually 72 dpi and in RGB color
PNG--a newer web graphic format for either photos or graphics with solid colors such as a logo, usually 72 dpi in RGB color
GIF--web graphics with solid colors and/or simple animation, usually 72 dpi in INDEXED colors
TIFF--used for print graphics, usually at 300 dpi in CMYK colors, many times used for layered files so elements can easily be edited
EPS--the usual format for what are called vector-based graphics built in Adobe Illustrator usually for print or sign applications, the term "vector" indicating mathmatical formulas build the art at whatever size and resolution the output machine uses
PDF--Portable Document Format developed by Adobe can be pretty much anything and is a pretty safe format for sending files to a printer
BMP--a PC-based art file not built for commercial printing, usually in RGB colors
DOC--a PC-based page layout file not built for commercial printing, would be better to save a Word document to PDF format if sending to a commercial printer
PUB--file from a PC-based program called Publisher, which many printers/designers won't have since they work on Macs, better to save as a PDF when sending to a commercial printer or graphic artist
ZIP--a compression format used to combine art and layout files into one, usually smaller file for sending over E-Mail or FTP
Everyone's An Artist is an effort to assist office personnel who have been thrown into the creative production world simply because they have a computer. For professional results, one should still hire a creative professional. My analogy: it's like throwing a hammer and nails at someone then expecting him/her to be a carpenter--sure, they can work the tools, but will the structure do what it needs to do? Hmmmm.