Final answer:
The number of posts with photos is 1/3 of the number of posts without photos.
Step-by-step explanation:
To express the number of posts with photos as a fraction of the number of posts without photos, we can use the information given. The social media director posts 3 updates with photos for every 6 updates without photos. This means that for every 9 updates (3 with photos and 6 without photos), 3 of them have photos. Therefore, the number of posts with photos is 1/3 of the number of posts without photos.