Hello again,
I know this thread is old, but I'm glad it's still here.
I'm using a RT template too, and was having trouble getting the article images to float properly using the settings in the article parameters. Just knowing that it might be Gantry causing the problem was a step in the right direction.
My solution was to add the following to my custom css file (This was to align the image to the left.):
.img-intro-left{
float: left !important;
margin-right: 15px;
}Just invert the 'left' and 'right's' to float it to the right.
Thanks for pointing me in the right direction,
Will