I’m not sure I understand the question correctly, so please feel free to correct me.
Assuming you are calculating the loss for each patch, then you should be able to print this loss during training directly or alternatively calculate the mean of all patches for the particular image.
However, based on your data loading implementation and shuffling, it might be challenging.
For evaluation you could compute the loss in the same way as during training.
However, for the prediction of each image, I would recommend to process all patches of the image sequentially, so that you can yield the right class after classifying all patches.