(Note: this is my first comment. It might be too detailed...) 1. I think the sentence is not strictly ungrammatical. However I find it very hard to imagine a context in which 'the pictures' should not be just 'pictures'. 'The pictures' would have to refer to a specific set of pictures already established earlier in the conversation. 2. "I've been to all the places of which you shared pictures." Seems to me perfectly OK in writing - but the 'of which' structure is pretty formal for speech. I would say "I've been to all the places which you shared pictures of". 3. There are people who would prefer 'that' to 'which' in my version of the sentence above. I think they would write/say "I've been to all the places that you shared pictures of". I think this may be more common than my version with 'which'. 4. If I remember correctly, these people use 'which' only for 'non-restrictive' clauses which just give additional 'By The Way' information, and don't define which places (in this case) you are referring to. These clauses with 'which' normally come between commas. They might say "I've been to all the places, which were really beautiful, that you shared pictures of."