오류가 생겼습니다

[Hyeongu02]

Pictures Downloading...
Traceback (most recent call last):
File "C:\Users\rkdgu\Desktop\XIN_Picture_Downloader-master\main.py", line 4, in
url = getpics.getUrl("./data/xinhtml.txt")
File "C:\Users\rkdgu\Desktop\XIN_Picture_Downloader-master\getpics.py", line 33, in getUrl
im1.save("./download/slide.pdf", save_all=True, append_images=imgs)
UnboundLocalError: local variable 'im1' referenced before assignment
라는 오류가 생겼는데 어떻게 해야할까요?