OK, since this only occurs sometimes, I couldn't test it yet with the broken images. But when everything is ok, it's like this:
are they pointing at the cache folder on your server?
Yes
Have you checked to see what's going on in the cache folder? So, you should find a folder ./cache/com_fabrik/staticmaps on your server, which has a bunch of 32 character .png file names?
I can find these images in the cache folder, all is ok. It only seems that the formatting changed. On my live site with J2.5 and Fabrik 3.09 they are named like you described
center=38.8387992,0.10505569999997988.zoom=8.size=300x150.maptype=roadmap.mobile=true.markers=38.8387992,0.10505569999997988.sensor=false.visual_refresh=true.png
On my test site with J3.4.1 and Fabrik latest GitHub they look like this:
e4a89616154ba82f62414b7912972bd1.png
Besides this, I tried to get Google Maps API to work. I got an API key, pasted it into the Fabrik options and then all maps and images are gone. So there is probably something wrong
I uploaded an image of the Google API overview, is this correct?
I checked the code of a site with static maps, you can find it here on my test site I provided it fabrik options
150401/index.php/fahrten
I can't find the API code as given in the Hello World example here
https://developers.google.com/maps/documentation/javascript/tutorial?hl=de#Loading_the_Maps_API
Am I missing something?
Hannes