1. Copy the famous pictures in museums.

2. Copy the famous pictures of museums.

3. In museums, copy the famous pictures.

(Does #1 mean #2 or #3? Is "in museums" an adjective phrase or an adverbial phrase? Thank you.)

#1 means to copy the pictures that are hanging inside the museums.

#2 means to copy some photographs of famous museums. (what they look like from the outside)

"in museums" is an adjective phrase, modifying "pictures"