You can upload an image, such as a jpeg or gif file, or a document, such as a Word doc or pdf.  The content author who uploads the file should take reasonable steps to make sure the file is not too big.  Unduly large files can ususally be avoided by understanding a little about the file types involved and saving the file in the right format.  If files are too large, then users (especially with dialup connections) will have trouble viewing pages and accessing information on the site.  Also, it will become difficult to manage and backup the data on the server, and we may have to pay for additional storage space on the web host server.

Some guidelines for file size:

• GIFs should be less than 25kb
• JPEGs should be less than 100kb
• DOCs and PDFs should be less than 20kb per page, unless they contain a lot of graphics

Another, closely-related issue with image size is the number of pixels that the file contains.  As a rule of thumb, if you divide the number of pixels by 100, that's about how many inches on the screen the image will take up.  Digital cameras often produce images that are 1024x768 pixels.  On the typical computer screen, that's about 10"x8", which is way too big to fit in a web page.  You will probably want to reduce a 1024x768 image to one-fourth to one-half of its original size for most web page display.  Doing so will also bring the file size into acceptable range.  Resizing the image file is not the same as changing the width/height attributes of the image link in a web page.  Resizing the file changes the binary data as well as the file size, and should be done before uploading the image to the server.  Changing the image link attributes only makes the image appear a different size in the browser, and doesn't make the web page more efficient.

There are several ways to resize an image file.  You don't need expensive complicated software:

• http://www.resize2mail.com is a free online tool for resizing images
• http://bluefive.pair.com/PIXresizer.zip is a program you can download and install for free
• http://www.bome.com/tools/resizer/ImageResizer111.exe is a program that lets you resize many images at one time
• If you have Windows XP, you can download a tool from Microsoft that allows you to resize JPEGs by simply right-clicking on them: http://download.microsoft.com/download/whistler/Install/2/WXP/EN-US/ImageResizerPowertoySetup.exe