Always show placeholder image in cms editor and amp

Hi, first all, fantastic plugin, I think is the best for charts with WordPress.
I have a minor issue. The plugin works well, but when I insert a shortcode always draw the placeholder image, not the png chart image. The same when I load an amp versión of post.

For example, this post loads normally: https://www.toca.news/2017/03/01/cosita/
The amp version: https://www.toca.news/2017/03/01/cosita/amp/
… but the png version exists: https://www.toca.news/wp-content/uploads/cosa-25-1.png

Settings are configured in “Performance: Default”

Thanks in advance!