So I have 6 imgs. When a user's mouse is over one of them I want to change the top

So I have 6 imgs. When a user's mouse is over one of them I want to change the top

When the user's mouse is off the image I want to return the image to its original position, If the user clicks an img I want to change its top position permanently (so long as the user is on the page).

Please how would I do this?