I can say that you don't need to restart the game to unlock these scenes. You can return to prior saves in order to get the ones you missed, and they'll appear in your gallery in the 'future'!
That being said, all but two of these are quite early in the game. Since I don't REALLY enjoy just telling people every one, as exploration is a big part of Grove... I'll just give you some hints for now.
1, 2, 4 and 5 are all unlocked BEFORE you rescue the blacksmith from the slime cave. Try exploring around more, putting on certain things... or losing particular battles.
3 and 6 are right near the end of the game, and also close together. If you have a save game in the 'mine quest' you can get both of these... pay attention to when somebody traps you in a room... and go visit the blacksmith after you finish.
Hope that helps.