Header and Slider Image Sizing

Regarding my site http://ve3eby.ca/ Today I installed Nepal Buzz Pro and I have been updating my image sizes. I have tried the recommended sizes of 1920 x 1080 and 1920 x 880 but in both the Header and Slider, the images are cropped as if the images I used were too large. I tried downsizing the images but the same result occurred. I have Full Size selected and even tried the other selections, under customize with no change. I have read the instructions and looked at the FAQ's without luck. Am I missing something here? Please advise. Regards, Paul Stuart