Bonjour @marcq.cyril6,
After having skimmed through the docs here Notion – The all-in-one workspace for your notes, tasks, wikis, and databases. my conclusion is that you will need 3rd party service to make this work.
The problem is that this API requires image to be sent in Binary format, and most probably returns the image in Binary format as well. Adalo Custom actions don’t support such capability.
Though I’d say that this integration is quite easy to do in Integromat. Also you will need to choose where to store the resulting image (it could be Airtable or AWS S3 or any other file storage).
Best regards, Victor.