Well, it is almost always the case when you want to resize your images to a concrete shape,
for example 224x224 (worth mentioning, that it is highly depends on which size your test images have).
I’ve used resizing too, when I encountered datasets with different image shapes.
By doing so, now you can clearly understand, which shape an input has and build your network.
For resizing you can you image = cv2.resize(image, new_size), see also
OpenCV resize function documentation 7