How can I make only the black contours "solid" leaving the rest explorable?

I have the image of a transparent MAZE labyrinth. This means black outlines and transparent internal parts. To avoid having to create every single wall as "solid"? How do you usually do to prevent my character from going through it.

Ho l'immagine di un labirinto MAZE trasparente. Questo vuol dire contorni neri e parti interne trasparenti. Per evitare di dover creare ogni singolo muro come "solido"? Come si usa fare di solito per evitare che il mio personaggio ci passi attraverso.

Are you talking about a Tilemap object?

You can set tilemap as solid and draw walls with it. Check out this demo:

howtoconstructdemos.com/using-an-invisible-tilemap-as-an-obstacle-map-for-pathfinding-capx