The point is to act as a gateway between visitors and media uploaded on supabase. Supabase is free but with a limit in the bandwith. This gateway will help store the images in CloudFlare, which is totally free. ALl images uploaded to supabase can be accessed like this :
Supabase URL : https://lvsbvjweppdlhmjuqqvt.supabase.co/storage/v1/object/public/medias/medias/detente.jpg
Gateway URL : https://images.coworking-metz.fr/supabase/medias/medias/detente.jpg
The system can be used for future others projects