Everyone was doing their own thing so I couldn't get any decent pictures.
Everyone was busy doing their own thing so I couldn't take any good pictures.
どちらも「みんな好きなことしていてまともな写真が撮れなかった。」という意味です。
1) Everyone was doing their own thing so I couldn't get any decent pictures.
2) Everyone was busy doing their own thing so I couldn't take any good pictures.
「好きなことしていて」は
be doing their own thing
be busy doing their own thing
などと言えます。
「まともな写真が撮れなかった」は
couldn't get any decent pictures
couldn't take any good pictures
と言えます。
ご参考になれば幸いです!