Yes, if you look in your Genesis Theme Settings page under “Content Archives” you’ll need to check the box that says – “Include the Featured Image?” then select the image size. If you need to add a different image size other than what is available in the dropdown list, you can do this by adding the sizes in your functions file. You’ll see something like this –
// Add new image sizes
add_image_size( 'featured-img', 630, 320, TRUE );
add_image_size( 'featured-page', 276, 140, TRUE );
add_image_size( 'portfolio-thumbnail', 264, 200, TRUE );
….just copy/paste, rename, and change the sizes like this –
add_image_size( 'blog-img', 250, 150, TRUE );
.
