See for example http://www.w3schools.com/css/css_background.asp
CSS properties used for background effects:
You seem to be mixing "specific" (-image) rules and "shorthand" background- rules. Believe, when you specify background-image, you do not include other aspects (such as no-repeat). Likewise, when you use background: shorthand, you have to include at least one other related property (such as color, position, etc.).
Also wonder about the one that has no position specified?