Verb conjugation of "umbauen" in German

Everyone says, that I am sending always silly pictures, so here 4 more images. Your picture is very cool, especially the hat, it has a really cool shape. Are there different sizes?
I looked at your site on the Internet. It is very beautiful, the graphics are interesting and the site leaves a clean impression. I think that paintings and art in general are very interesting.
I once had a lesson with a private teacher, but unfortunately she could not come regularly. She was always sick, then I have visited a school in Andalusia, which was worthless, since we talked only German.