I m working on an application which renders google maps on an image as below
As commented by Pointy, you need to use an API key with all referrers allowed in order to use Static Maps.
You can achieve that just by removing all the referrers from the list of authorized referrers. Or just create a new API key and use it without further configuration.
More info at the Documentation
I had the same issue. I used this instead of this and that resolved the issue. Some other api parameters didn't work on the second URL either (specifically marker styles), guessing the old API is deprecated
Would also recommend using https as opposed to http. This way your users wont get cert warnings if they view the page over SSL
From june 2018 you have to configure a billing account to continue using Maps static API; google "donate" 200$/day of credit Maps Static API Usage and Billing
add key in the url is not enough