Set height of featured image

I have a two-part question, but I think I have the first part answered.

1. I would like to have the featured image displayed on the front page, but not on the single post page. It appears the following code will make that happen, but I am not sure if I need to change the code to make second part of my question work.
.page-header-image-single {
display: none;
}

2. I would like to control the size of the featured image on the front page of the blog. I want to set a max-height and max-width, and I think I also want to be able to control the actual height of the image. The images now show up very large and I find them to large to scroll through conveniently, so I have temporarily disabled them. I think I can use to following CSS, but I am missing the callout for the image on the front page. Everything I have tried has had no effect on the size of the image.
max-height: 100%
max-width: 100%
height: 300px

So far in the blog process I have not purchased any of the add-ons, so I am making my modifications through CSS.

Thanks for the great theme and support site.