If you were going to save an image then send it over the Internet you wouldn't want to send a 10GB copy because it won't work so you would want to send a 1GB so they can be able to receive it and open. To make the files smaller you can change the size of the image and the quality and this will make the file much smaller. you could also change the DPI of an image and even the file type, but the numbers of colours in a image make the most difference to the file size.
You can make your job easier because if you have a lot of files to keep tidy you need to be able to sort them into tidy folders that can optimise your work place so you can see what file is the right size for the job your doing. Also if you need to find an image quick and you have named it this makes the whole prosses easier and if you have more than one file you need to put more than "1" after the file.
