I want to train a CNN for image recognition. Images for training have not fixed size. I want the input size for the CNN to be 50x100 (height x width), for example. When I resize some small sized images (for example 32x32) to input size, the content of the image is stretched horizontally too much, but for some medium size images it looks okay.
What is the proper method for resizing images while avoiding the content being destroyed?
(I am thinking about padding images with 0s to complete size after resizing them to some degree keeping ratio of width and height. Would it be okay with this method?)