Betheme safari - is crashing a few times! Need help!

i’m working with Betheme - “safari” is a one page design. After few times loosing some parts of it, i restore the website now i’m on the latest version and again is something wrong! The Background pictures get in the wrong size on her own and i don’t know why and what is wrong! I’m scarred to loos again parts of the side!

Sorry my english is not perfekt i’m from Germany.
Would be great if someone help me.

Here the you can see the probleme