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 ? 

Web designers usually decide to let images fill 100% of the available width of their containers. But there can be white space on top and bottom, or the image can be truncated. In order to avoid white spaces, a more advanced way to address this problem is to use javascript to decide when the image should be enlarged in height or in width to fill its container, and then to center it vertically or horizontally. This is how the Customizr theme and the Hueman theme handle this problem, but this still doesn't solve the truncation problem. When white space is not a problem, then the image can be displayed in its natural dimension, for example when displayed inline in a post.