My pictures are truncated, what can I do?
WordPress themes uses specific image sizes. If you just switched to a new theme, you need to regenerate your thumbnails images for your new theme, otherwise images may not be sized the right way, or truncated. There is a free, effective and safe plugin to solve this issue : Regenerate Thumbnails.
The fact that images are not displayed the same way on different devices is normal. The worse thing that can happen to an image is to be stretched horizontally or vertically. The problem to address is : how to display an image with fixed dimension in a container that can have a variety of dimensions, depending on the device used to display it ?