How to export the trained model for cv2 use in python 2.7?

how to export the trained model for cv2 use in python 2.7?

and how to use the exported trained model for cv2 to use,
if using example below to recognize a number in photo?

What do you mean by cv2? OpenCV?
OpenCV does not support NN models, maybe you meant Caffe2?

Or did you want to convert images to cv2 format?

Let me know,

yes opencv do not have NN model
can opencv use NN model from pytorch? or do not need to export , just import pytorch library , directly use with opencv?

no, not want to convert images

if opencv2 can use NN model from pytorch, is there any requirement to manipulate the photo in real practice?
as i find pytorch example and mnist 's image have been compressed in another format, i do not know which
treatment have to do before using NN model in pytorch