When a girl responds with "Yes for sure!" and includes a snap of her laying down smiling on her bed, it could mean a few different things:
She's excited and looking forward to hanging out: The smiling snap could indicate that she's happy and enthusiastic about the idea of spending time with you.
She's comfortable with you: Laying down on her bed might signify that she feels relaxed and at ease with the prospect of hanging out, suggesting that she trusts you and enjoys your company.
She's being playful: The snap could be a playful way of expressing her agreement to hang out, adding a fun element to the conversation.
She's busy at the moment: Alternatively, she might be indicating that she's currently busy or relaxing in her room but still eager to meet up with you later.
It's essential to consider the context of your previous interactions and the nature of your relationship to better understand her response. If you're interested in pursuing a deeper connection or relationship with her, it might be a good opportunity to plan a fun and engaging hangout to get to know each other better. Remember to communicate openly and honestly to ensure both of you are on the same page regarding your intentions and expectations for the hangout.