Picrites are a form of currency used in the game. You can earn Picrites in the game, or you can purchase them on the Nintendo 3DS eShop. As the game is free to play, it's not necessary to purchase all the Picrites as they can be easily gained in gameplay, but purchasing them does allow for faster progression.
Picrites can be gained in the game by completing many tasks. If you earn a medal, you'll get some Picrites. If you complete challenges on any of the stages, you earn Picrites. You can also purchase Picrites in exchange for real money.
Picrites are used for two specific things in the game. These will speed up your gameplay and stop you having to wait for time to pass
The first feature is the ability to recover your Pokémon. After they have been used for a skill, then they will have to wait a period of time before they can be used again. Using Picrites, you can forgoe this period and heal your Pokémon instantly. Do note that Legendary and Mythical Pokémon cannot be recovered using Picrites. You also have to spend 300 Picrites to get to the Alt World and 500 Picrites to get the Mega Pencil to complete Mega Evolved Pokémon stages.
Picrites can also be used to recover your Energy metre. Whenever you make a move in a puzzle, your metre will go down and you'll have to wait for it to replenish. If you spend 10 Picrites, you can have it recover instantly. You can also use Picrites to upgrade the metre to get more energy on it. There are 5 different levels.
Picrites can also be used to open access to the next area. Every area requires spending Picrites to unlock.
As the game is free to start, you can put money into the game in order to obtain Picrites. This will allow for you to get through the game at your own pace without having to wait for the timers to run out. This can be done simply in the Shop option of the game, accessible at any time both during a puzzle and in the overworld.
There is a spending limit to this game. You can only purchase up to 5,000 Picrites in the lifetime of the game. Once you have done this, however, you'll be able to get free Picrites. You'll then be given them in batches of 1,000 until you hit 8,000 in your pack preventing you from running out of them at any time in the future game play.