Hello,
I hope you were able to submit this Kaggle.
I am in a similar situation as you - trying to submit my first Kaggle competition. I have a similar problem (link) and I created a discussion for it.
I was able to create a CustomDataset that return an image and a label (both tensor). Then I pass them to the Dataloader, but then, we I get the Image and Target from the Dataloader in the BackPropagation, the size is not right.
This is the link to the github so I can track my progress
Any ideas, suggestions?