# Exporting JPG image from LaTeX SRC-block with :async header

I like to generate JPG images from my LaTeX/tikz drawings in my org files. For this, I use constructs like

#+NAME: my image

This works fine, but the evaluation takes some time and I like to do it asynchronously. Therefore, I tried adding :async with ob-async to my SRC block header. But then, I get an JPG image of my typed tikz code instead of the drawing. Why is that and how can I export my images asynchronously?