Q: "Three young men stand against a wall talking while one young boy looks forward holding a poster." Does this mean that "The young boy is holding the poster for the other guys to see."?
A: it is not possible to tell

Q: "Four women in bathing suits are playing on the beach." Does this mean that "Some women are sunning themselves on lounge chairs."?
A: no

Q: "Two men sitting on a bench talking, with a billboard advertisement for glasses in the background." Does this mean that "commercial signs are in view"?
A: yes

Q: "People are sitting on a grassy ledge, while others are walking in the background." Does this mean that "People are sitting on the grass."?
A:
yes