This will only be for the Pictures not unlocked by the time you Finish the game.
The conditions i finished the game at but still didn't have them were,

• Finished All Wishes.
  
• Acquired All Skills Available Before Knighted.
  
• Acquired All Aftercare Skills After Knighted.

Firstly,
The conditions in which i confirmed are required to acquire them.

• The knighted girls can have any options set when you acquire them. (only tested "None" & "Be Quiet")
  
• The score acquired by the specific mini-game needs to be 200.
  
• The picture will be acquired even if you return to menu without saving.
  
• A save must made after acquiring the pictures to keep them even after you exit the game.
  
• The save required to keep the pictures does not need to happen in the same run you acquired the pictures from and can be done anytime after acquiring the pictures but before closing the game.

Bottom Row, 2nd Picture (Left to Right)
Tingling Course

Bottom Row, 3rd Picture (Left to Right)
Gooey Lesson

Bottom Row, 4th Picture (Left to Right)
Electric Flick

Page 1 - Kisaragi Knighted
Page 2 - Ran Knighted
Page 3 - Either Alice/Shin Knighted but probably Alice
Page 4 - Tomoe Knighted
Page 5 - Sako Knighted
Page 6 - Yuko Knighted (Only Tingling)

After completing these + the original 5 per page i had,
it totalled up to 46 Pictures.

Hopefully this will help you get those missing pictures without having to punish all of them.