Switch it to RGB from CMYK. RGB is for the light emitted from a computer screen. CMYK is for printing.
Save it as .JPG or .PNG depending on what you want. (Depending on if you want to make a person wait or not) JPG is quicker and easier to see and load. PNG is compressed without losing the resolution and such yet takes forevs to load.
[img]www.blahblah.com/some-random-image-website.jpg[/=img]
Minus the equal symbol.
-Sin