Image resizing and padding for CNN 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?)
This question on stackoverflow might help you. To sum up, some deep learning researchers think that padding a big part of the image is not a good practice, since the neural network has to learn that the padded area is not relevant for classification, and it does not have to learn that if you use interpolation, for instance.