Like any other file that stores data, the size of a Joint Photographic Experts Group, or JPEG, file is expressed in bytes. According to the metric system, 1,000 bytes is also called a kilobyte, or KB, and 1,000 kilobytes is called a megabyte, or MB. If the size of a JPEG file is expressed in megabytes, you can convert the size to kilobytes by multiplying by 1,000. For example, a JPEG file that's 5MB is also 5,000KB in size.
Reducing JPEG File Size
When you open a Web page, the Web server sends the contents of the page to your computer. The larger the JPEG files on the page, the longer it takes for the page to load. By converting JPEG files that are measured in megabytes to files that are measured in kilobytes, a website loads more quickly. To shrink a large JPEG file, open the image in Paint and choose "Resize" in the Image group on the Home tab. Adjust the height and width or choose a target size based on the percentage of the original file. Select "Maintain Aspect Ratio" to maintain the relationship between the photo height and width. Save the file and compare the file sizes.