Maybe there were some issues moving these files to the server?
Could you try to load all images in a loop, store the index which gives you the error, and have a look at this particular file?
Something like this should give you the index:
for idx, (data, target) in enumerate(dataset):
    print(idx)

The error should then be related to idx+1. Depending on the Dataset you are using, you could try to get the corresponding image path and check the file manually.