What is the cause of EOFError?

raceback (most recent call last):
File “train.py”, line 259, in 
main()
File “train.py”, line 254, in main
trainer.validation(epoch)
File “train.py”, line 159, in validation
for i, sample in enumerate(tbar):
File “/home/uts/.local/lib/python3.6/site-packages/tqdm/_tqdm.py”, line 979, in iter
for obj in iterable:
File “/home/uts/.local/lib/python3.6/site-packages/torch/utils/data/dataloader.py”, line 637, in next
return self._process_next_batch(batch)
File “/home/uts/.local/lib/python3.6/site-packages/torch/utils/data/dataloader.py”, line 658, in _process_next_batch
raise batch.exc_type(batch.exc_msg)
EOFError: Traceback (most recent call last):
File “/home/uts/.local/lib/python3.6/site-packages/torch/utils/data/dataloader.py”, line 138, in worker_loop
samples = collate_fn([dataset[i] for i in batch_indices])
File “/home/uts/.local/lib/python3.6/site-packages/torch/utils/data/dataloader.py”, line 138, in 
samples = collate_fn([dataset[i] for i in batch_indices])
File “/home/uts/dev/kelvin_git/glasses_segmentation/pytorch-deeplab-xception/dataloaders/datasets/yutu.py”, line 38, in getitem
img = Image.open(self.images[index]).convert(‘RGB’)
File “/home/uts/.local/lib/python3.6/site-packages/PIL/Image.py”, line 915, in convert
self.load()
File “/home/uts/.local/lib/python3.6/site-packages/PIL/ImageFile.py”, line 250, in load
self.load_end()
File “/home/uts/.local/lib/python3.6/site-packages/PIL/PngImagePlugin.py”, line 677, in load_end
self.png.call(cid, pos, length)
File “/home/uts/.local/lib/python3.6/site-packages/PIL/PngImagePlugin.py”, line 140, in call
return getattr(self, "chunk" + cid.decode(‘ascii’))(pos, length)
File “/home/uts/.local/lib/python3.6/site-packages/PIL/PngImagePlugin.py”, line 356, in chunk_IDAT
raise EOFError
EOFError