Face it.  You need to know about file types.

The TIFF format is recommended for archiving and printing images. TIFF is a high-quality uncompressed format required for major publications and other professional printing uses. If you produce all of your digital images in this format, they will also be useful for less demanding products like newsletters or the WWW after file conversion. But the file sizes are large; about 20 MB is preferred for professional quality printing of an 8"x10" image.

WMF (Windows Metafile) is useful for all graphics (maps, drawings, and logos) except for those used in major publications.  WMF should not be used for photos.

At the lowest end of the scale is JPEG or .jpg, a compressed file format that was developed for photographs on the WWW.  The JPEG format uses compression and the files sizes are smaller, but information is lost in the process. It works well on photographs, naturalistic artwork, and similar material; not so well on lettering, simple cartoons, or line drawings.  The files look good on the computer display but to use them for more demanding products, especially printing, can be a challenge, if not impossible.  Images copied from a website, for example, cannot be used for posters or publications without severe image degradation.  JPEG files can be very good on a computer display with only a 20K file size and are recommended for photos.  For e-mailing images or use on the Web, JPEG format is best. One drawback to JPEG format is, each time the file is opened, changed and saved, the JPEG compression scheme is run again and image quality is reduced each time. If you edit the same JPEG file several times with each edit/save cycle, the image quality deteriorates further.

GIF files were designed to use on the WWW for graphic elements like stripes, dots, and icons.  GIF file sizes are even smaller than JPEGs since less detail and fewer colors are used.  Printing enlargements is not an option.

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