Thanks a lot! It fixed my problem by writing the following in my index.html file:
<img src="my_folder/static/something.jpg">
The missing part in my tests was my_folder which represents the name of my app (the folder where it is self-contained). I didn’t realize that by ‘the path is app_name/static’ you meant that the path I had to write in the html file was exactly that - I thought you just meant I had to create the static subfolder inside my app folder and that’s it.
Thanks again