You think this is a bug Chelsea. Maybe what you experience is a bug but it is also possible what you see is a result of your coding/layout and how you 'save your work every time I make a change".
We cannot tell unless you share an image of your Blocks here in the Forum and show how you populate your 'picture buttons' . It might be necessary to post your aia file from the Project or from a subset of your Project that shows the problem. Also, since this is a course you possibly paid for, you might ask your question of Shaw Academy. We have nothing to do with Shaw Academy or their course but if you provide some information about what you are coding using App Inventor, someone in the Forum might be able to help.