There are many formats for storing graphics. This creates problems, but the commonest cause of dissatisfication with graphics is simply that their quality is determined by the computer's way of displaying graphics. Most PC machines running windows will only use a limited number of bits to store colour information. If you are running in a 256 colour setting (or fewer), no colour graphics will look good. A match between the bits that were used when a graphic was created and the number used when it is put on the screen is vital and will render all other issues secondary.
After understanding that, there are two other important things to grasp: one is that graphic images often involve a huge amount of information, i.e. require very large files for storage; the other is that they can be stored either simply as a "bit map" or as a series of instructions about how to draw the graphic. The second approach may simplify things if the graphic is a collection of lines but may make the size problem greater if the image is a collection of dots. Chosing a "bit map" format for line graphics is a mistake, using a "vector" or "page description language (PDL)" format for something that starts as a bit map (i.e. photographic images, video material, and faxes) can also be a mistake. BMP and WMF are the commonest Windows bit map and vector formats respectively. Neither is a particularly good standard for quality graphics or for transportability between packages and machines.
"Vector" or "PDL" methods can give some considerable degree of "device independence". That is, with appropriate software and hardware, the final form may be very similar on screen, on paper or in a transparency. The most important format is Encapsulated Postscript (EPS). An EPS file can be imaged or printed by any device that supports EPS at the maximum resolution, range of colours and fonts available. Furthermore, good sofware/hardware can substitute fonts of the general type (such as point size, face, & serif) to allow a reasonable facsimile of the original document when original fonts are not available. EPS file creation is an option in most good Windows and Mac graphics packages. (To confuse things, a true EPS file has both the Postcript instructions to draw the image and a small bitmap image that can be used to display a quick and dirty on screen an approximation to that image.) EPS has spawned a derivative format: "Acrobat". This combines much of the power and device independence of Postscript and EPS with the hypertext power of HTML (see the document on WP formats). Acrobat reader programs for Macs and PCs are available. The latter is on the School server as a self-unpacking executable file.
Two other file formats have become common. The first is GIF, the format used in CompuServe and used for most graphics in HTML documents. The second is TIFF which is available in all microcomputer-based graphics programs. Unfortunately, the TIFF standard is not standard is often honoured in the breach which causes problems. Despite this software exists that will readily convert images between a huge variety of TIFF and other formats (such as HiJack Pro). It is hoped to provide such a package on the network or to provide a copy of the popular Corel Draw! package which will convert between many formats by reading and writing to them even though its own format, ".CDR" is not a recommended standard in the School at present.