Let's see if I can confuse you further
![Wink ;)](./images/smilies/icon_wink.gif)
Don't worry, someone will come along later with a link to a good description.
DPI stands for Dots Per Inch. It is
only relevant to
printing a physical copy of your picture and it will depend on the printing process you use if the settings you save in the image will be used at all.
When you are preparing pictures for the web the only considerations are the width/height in pixels (i.e. 1024 by 768) and sometimes the overall file size if you have storage and/or bandwidth constraints (How many megabytes etc). If you are concerned about image theft then consider adding a watermark as a fairly decent print can be made from a relatively small image - 600 pixel wide image printed 6 inches wide = 100dpi, which is a quite acceptable quality.