VanFrikschoten

Thanks for your reply. Indeed, it started to work after a new image was uploaded. So, no more issues here and very happy with this plugin! Thank you!

@mod: sorry, I wasn’t aware of that. Here’s the code thru pastebin:
https://pastebin.com/2ZiHFZwB

This might solve your problem:
Check wp-content/themes/
You’ll see there these directories:
mobile-pack-base, blue, green and red
Are they empty? Then upload in wp-content/themes the same directories (mobile-pack-base, blue, green and red)that live also here: wp-content/plugins/wordpress-mobile-pack/themes/
chmod the directories 777