A. BMP( Bit Ma P) is a simple image, or picture, format developed by Microsoft for Windows and usually opens in the Microsoft Paint program. Pictures copied from the Web may sometimes be saved as .bmp files. Bitmap pictures are made up of tiny squares called pixels; they are usually fairly large files and are not compressed. BMPs can have up to 16.7 million colors, depending on the resolution.

GIF(Graphics Interchange Format) was developed by Compuserv for color Web images to replace their earlier RLE (Run Length Encoded) black and white images that I remember from the Texas Instruments TI 99/4A days. GIFs are also bitmapped images, but are limited to 256 colors, making it an unsuitable format for photographs. However, because GIF files can store multiple images in one file, they can be animated and thus we get graphics that dance and fly in e-cards, e-mails, etc. Compression makes GIF files smaller, move across the Internet faster, more suitable for slow modems, AND the compression algorithm, or formula, allows the file size to be reduced without losing quality. GIF is normally used for diagrams, buttons, etc. that have a small number of colors.

JPG (Joint Photographic Experts Group) was developed by a committee known as the Joint Photographic Experts Group for storing and transmitting photographs on the Web and is the standard used for these purposes. This format allows major reduction in file size, but also results in a loss of quality, thus the term “lossy compression.” Each time a file is saved in the JPG format, a question is asked about how much compression to use; as it loses pixels, it loses quality of resolution. JPG is not well-suited for drawings, because they get distorted in the compression process.

PNG (Portable Network Graphics) is a bitmap image format with “lossless compression” that doesn’t lose pixels each time it’s saved and compressed like JPG, and it isn’t limited to 256 colors like GIF. PNG was created in 1996 by the World Wide Web Consortium to improve and replace GIF; it is now the number three format used on the Web, behind JPG and GIF. While PNG files can’t do animation, a companion format, MNG (Multiple-image Network Graphics), does.

TIF (Tagged Image Format) , developed originally by Aldus and Microsoft for desktop publishing to get scanner venders to use one standard format instead of everybody having proprietary formats, is now adapted by Adobe Systems. TIF is widely used by photo editing and layout publication programs because it can handle multiple photographs and line art together in the same file. TIF files do this by using “tags,” or descriptions in the file headers. This capability to store image data in a lossless format makes TIF files a useful method for archiving photos as files, and can be edited and resaved without suffering a compression loss. Other TIFF file options include multiple layers or pages. I try to save my scanned files as TIF because so many programs, including my CreataCard and Family Tree Maker programs, can use them.