In the layout-editor you see on top in the ribbon (when you look at the layout and in the tab view) a checkmark with 'Show collision polys'. Check it and you will see red lines that stand for the collision polygones.
If they look a bit messed up. Then double click the sprite to take you to the sprite editor. Choose the last tool on the left. Wich is for changing the collission polygones. Rightclicking and set them to the bouning box, will do in youre situation. Or change them to tour liking.