Image resolution 72 dpi or 96 dpi or ppi (pixels per inch)
Image file types: jpeg, png, pdf, gif, tif, tga, psd, NEF
Vector images: ai, eps (if sending these types of files pixel dimensions are irrelevant)
Text files: doc, odt (Open Office), html, txt, rtf
cdr files (Coreldraw!)
Powerpoint files (ppt)
Anything created in a program submitted in its native state (i.e. a file created in Publisher and submitted as a .pub file).