There are available walkthroughs online if you know where to search. However, they are only until v0.18 so you may need to figure out the rest that are for v0.19 onwards. You may also ask here or other forum sites for any pics you are still missing.
I already unlocked all 661 available pics for v0.21 and mostly familiar on which path and dialogues to get them, so you may also ask me directly for the missing pics you are looking for.