Click on a item on workplace, then you open Mat. Editor and use Import Texture on Main Text. You can do that with most of studio items, but the most popular image holder is Image Plate.
You can resize it with Scale XYZ.
Could you please elaborate your second question? I think something was lost in translation, are you talking about the characters´s bones deforming in certain scenes? If yes, I imagine the fix depends on the type of the scene... Is it a normal, timeline or vnge scene?
I don't know much about studio scenes, but if you can elaborate the problem, maybe someone here will help you better.