Custom theme blog image size

Hi,

I have created a custom theme for certain categories in my easyblog. These categories are populated by feeds and so don't come with their own blog images. I want to use the placeholder image for these category posts. On my main pages I use full width images, but in this custom theme I want small thumbnail size images to the left of the text. I have added the following code to my nomad/css/custom.css

div#fd.eb-view-entry .eb-post-image{
float: left !important;
width: 30% !important;
}

But this has no effect.

Also, is it possible in the custom theme to have an alternative placeholder image (I am thinking I can create a custom theme for each of my special categories and set individual placeholder images)

Kind regards

Mel