Is it possible o change Picture Style?

Hello, I started my first WP-Project und use the Fotografie Pro theme. At my start page I want to insert my "portfolio" (4) with the pictures added to the different portfolios.This works fine...... But I want the picture style from the "Post" pictures style - with the light grey /transparent bar across the picture and "postname and date in it". Is this possible? Or should I use the "posts" instead of "portfolio". I use this in the moment... (under construction - www.lichtbildundmeer.de)? Thanks a lot Andreas (Germany)