Using SVGs in images placed in blocks

I want to use SVGs inside an image element used inside blocks.
How is it possible to activate SVGs inside of blocks?

Uploading and using SVGs in an image block should actually work out of the box. What exactly is the problem?

The problem was, that i could not select an SVG file for uploading. Now it is solved …
I created a new custom block which extends the core image-block and uses a own file-template.