Why do 17 look so small on the M6?*see photo*

Hello guys, now I borrowed 17 ‘er to see what they look like.And I have to say.(sc….)I don’t like it at all.There my 15 ‘ he winter tires look even bigger.What can this lie on.On dm photo you can see: 215/40ZR17 rim: 7,5J 17HZ/ 114,3, ET40. Should it be 18 or 19? I don’t feel like the wheel box is so full. or what do you mean? ***Merci already***