Question about get The first class img src

Question about get The first class img src

Hi everyone, 
First post here, I have 2 html docs the first one has a div with class "Img-container" and The second html has a div with class "Img-copy", how can i do to get The first class img src and get it on The second class when: I click a next Button on The first html that links to The second OR when The second html loads?
Thank's a lot!