Images dissapearing on frontpage!

Hello,
can somebody help me perhaps with this strange issue? I desperately spend 30 hours the last days to figure out why the images are not shown on the frontpage (http://web1528.fge1.5hosting.com/planM). Ok, the most time i spend with trying to backing up the site with upfront pro, what suddenly didn't work anymore because a "no responsing error". At least i got it with All in one Migration Plugin, made some changes and trials and it works on my localhost again. Then i remigrated all on another webhoster (http://www.klettern-blinde-leitsystem.at/_freshWP) but it is the same. On localhost i have renewed my mamp and php 7 is running, on the webhost (klettern …) i've the same php7.0.0, also tried to switch back to php5.6, but that doesn't helped. I've read somewhere something about javascript errors, but if that would be the case either on my localhost it should appear.
If somebody has a hint i would be very appreciated, i'm on my wit's end.
I could make an admin access if that would help.
Theme is "Enfold" from Kriesi, WP version is updated to 4.5.
Thank you
Markus