I'm running Version 0.8.8h on a Rasberry pi3(rasberian) with PHP7 and whatever the version of mysql that is on the repositories for apt at this time..
Initial setup was a breeze and I managed to get my first devices and graphing sorted easily enough.
This all lasted till last night when I was workling on exporting graphs to the apache web root directory (this also worked well) when I noticed that the graphs in the tree and preivew view were not presenting properly
forefox comes up with
and chrome with 
the chrome image leads me to believe i have a broken thumbnailwhen you click on one of these links the graphs display normally so i at least know its not the graphs themselves thats the issue
so my main question is ... is there a reset settings to defaults option somwhere that i can use to remove all my "tweaks" or does anyone know what setting may have caused this ... i have been through most of them and put them back to what i think was the origional value ... but who knows how many times i adjusted something before i noticed i had an issue.
im at the stage where i have looked in a whole lot of places and if i cant find somethign soon i will simply pull cacti off and blitz all the conging files and start from scratch
Cheers