!important
if for overriding higher priority attributes, and not for higher level attributes. An example: something specified in the
style attribute overrides what's specified in the css class. Also css class name order in the
class attribute is messing up the effective style. As well direct specification will override cascaded one. But if you have an outer element with any css specification and an inner element with an other one, the inner specification will simply override the inherited one. So you have multiple choices.
But anyway specifying
background-image: none !important;
will have it's effect, if any other higher priority specification is not available on place.
Update:
According to your code posted, you are using the style in a wrong manner.
<span class="style28"><img height="30" width="30" src="http:
After all it is not wise to mix css, inline style and inline formatting attributes.