For the Holyoke-Reaves project, the author decided to use JPEGS for all images, because they are small and are widely accepted by browsers.

1. TIFF (.tif): Tagged Image File Format. The TIFF format allows for high-quality images up to 24-bit color. It is standard practice in institutional digitization projects to create master images in the TIFF format and create copies in other formats to actually be used. If you have the space (CDs or zip disks), scanning into TIFF and then changing formats to jpeg or gif is not a bad idea. Some browsers will not recognize TIFF files.

2. JPEG (.jpg): Joint Photographic Experts Group. Used for the display of color images. They support 24-bit color depth, but allow for compression (thus making the file size smaller) though this does reduce the quality. JPEGs employ a dual compression and decompression algorithm. So-called progressive JPEGs allow for a speedier display as they load in a low-quality image first and gradually build up the blocks of the graphic increasing its clarity and quality. Here is a JPEG file.

You will notice that the JPEG file and the TIFF file are identical to the eye. If you right mouse-click on each of the images and view "properties," you will see that although they contain the same number of pixels (351x218) the TIFF file is much larger: 185056 bytes compared to 18854 bytes for the JPEG. Depending on the speed of your computer, you may have experienced a slower download time for the TIFF file as well. These are issues to keep in mind when selecting which files to use in your site.

3. GIF (.gif): Graphical Interchange Format. Used mainly for line art or greyscales. GIFs only allow for 8-bit images. They can use a feature known as interlacing which, like with progressive JPEGs, allows one to display a low-resolution image first and then gradually fill in more detail. Because of their relatively low resolution, GIFs work well with simple color files, or images in shades of grey (such as the one here).

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