How to test my own low resolution pictures (without high-resolution downsampling)?

[zymize]

Sorry to disturb you.I have one question.
How to test my own pictures using this code in tensorflow or pytorch? I want to restore my low resolution image to reconstruction ×2 resolution. In my opinion, the test is always to downsample the high-resolution test set to 2 times, and then reconstruct it. I don't know how to directly input my own low-resolution image (without high-resolution downsampling),and then reconstruct it to twice its original resolution?
Looking forward to your reply. Thank you very much.