The problem here is with image objects. It matters how you select them. If you select them the wrong way, you get no selection handles, or scaling handles.

Using just the regular selection tool, if you Shift + drag over one image object to select it, then shift drag over another image object, you get no selection handles for scaling. If you shift drag over both image objects you also get no selection handles.

If you shift and click on one image object, then shift click the other, it works fine.
If you drag a single selection over both image objects it works fine.

If you are selecting a vector object and an image object, it only works properly if you first select the image object. As long as the image object is selected first, it doesn't matter how you do the selection, clicking or dragging. It always works. But, if you select the vector object first, it will only work if you click on the vector object first, then shift click on the image object. Or, drag a single selection over vector, then image object next.

If you