dvduinen

@ Cais,

Thanks for the reply! A couple hours after after i posted this problem there was some kind of wordpress update. After i updated, all problems were solved!

Very very strange, but im happy!

Marked as resolved ??

Another edit: i deactivate all plugins, changed theme back to twenty fourteen and tried it again without succes, same as the “Flash slideshow support has been removed from NextGEN Gallery.” announcement, it won’t disappear.
– Deleted en reinstalled the plugin, no succes
– back to factory settings (in Nextgen menu), no succes

im getting desperate now :-)!

Solved! I just adjusted the width of the background thumbnail ??

Thanks for the answer, it did work for me :-)!