Size image

What size I need to use for good image view. I loss proportion. And I want keep original size of picture. I whold like make one high size.

All images must have the same proportions. Please prepare images in image editing software before you include them in Carousel.

Thaks for fast answer. I understen that, but i looking fastes way put image to web. And your module I like. I had before one, I do' not like for long work befor put in web. It look like that. I ges you can do it. And may i can put link for pictures.
I send example what I have.