As far as I know, after a question tag we put a question mark and then start a new sentence.
I think the first one is correct, but I’m not sure. Just wait for the others to answer your question.
Let’s turn this around for a second.
“Looking at all these pictures is fun, isn’t it?”
“Looking at all this pictures” is just explaining what she means by “this”, so I would keep them in the same sentence as in the second example.
“This is fun, isn’t it, looking at all these pictures?”
I would get rid of the “Ha, ha, ha”, though. She certainly doesn’t say this. If anything, maybe include “[chuckles]”.
About the only time someone would actually say “Ha, ha ha” would be sarcastically, following a rude comment.
“Ha, ha, ha. Very funny.”