Photo order on posts

Hi there, in the following post I had a big problem to put the photos in the order I wanted to have them. http://costa-vertical.com/en/barranco-de-relleu/ The thumbnails incl. description and the two photos with the green water I wanted to show next to each other, but it just didn't work. I tried the following: 1) Thumbnails - I moved them all next to each other without description which worked on the dashboard, but as soon I did the preview they were all beneath each other. 2) Thumbnails: I put them next to each other, but as soon I put the description they've already jumped beneath each other even on the Dashboard. 3) Photos: The same like 2) for thumbnails. Please, could you give me a hint how I'm able to manage that? Have to do the German post anyway and don't like to have the hassle again. Thanks a lot in advance and kind regards, Kris