My veneers look too big? (Photos)

Yes you can have these adjusted to appear smaller. Hard to tell without seeing your entire face.

Yes, you can have your veneers shortened and have them made to look smaller.  Asking whether or not your dentist did a good job would be impossible to answer without seeing them and checking them to make sure that your occlusion is right and the veneers are sealed properly.  Also, if you are happy with the shape and shade then that's great! However, if you are unhappy with them, see your dentist to see what can be done.  

Good photos, but not any photos to compare to - either of the temporaries or your original teeth.From the images you have presented, the veneers look good!

the exact size and proportion of your teeth is hard to judge by your photos and without understanding of what you started with it's hard to make a judgement . Often a case like this we see four veneers were placed when a better smile could have been achieved by doing six teeth.   The more teeth veneered allows the dentist and ceramist to make a smile look more natural by proper proportion and spacing. 
They thing I see the most is the teeth are monochromatic (one color) and their shape could of been improved by possibly reshaping or contouring the teeth. 
But without knowledge of what you started with, what limitations your dentist had. Ultimately, it's hard to truly judge.

Hi:From the limited photos you have provided, the veneers look good.  Making the veneers shorter is an easy adjustment.Best,Dr. Maddahi