How do I get the action button input for the event contents?

I'm new to RMMV and need help with a specific kind of event

What I want to happen is:

• Player interacts with event (object)
• Text appears
• When the player presses the action button (z/space) to finish reading the text, a picture will show up
  
• Wait for the player to press the action button (z/space) again to erase the picture
  
• Resume gameplay

I've got the interacting with the event, the text appearing, and the picture popping up to work perfect; but I can't figure out how to wait for the player to press the action button (z/space). The image will just stay on the screen and the player can move around like normal. How do I get the action button input for the event contents?

After your show picture, make another show message command but dont put any text in it and set the background style to transparent, that will make your game wait for another "OK" button press before proceeding to next command, then put erase picture after that blank show message