For images, the Origin sets where the image aligns inside its box. You set it in the Position & Size section of the Property Panel, using a grid of nine points: the corners, the edge midpoints, and the centre.
Origin only has an effect in Contain mode, where the image is smaller than its box and there is empty space around it. In Cover and Stretch the image fills the box completely, so the Origin makes no difference.
This matters most for logos that come from an image input field: your users upload logos in all shapes and sizes, and the Origin keeps them aligned the same way inside the box, for example always centred, or always pinned to the bottom-left.