segfault when importing *.tif as book cover

[Alan Aversa]

Calibre 7.10:

Traceback (most recent call last):
  File "calibre/gui2/ui.py", line 147, in __init__
  File "calibre/gui2/ui.py", line 165, in init_iaction
  File "calibre/customize/__init__.py", line 659, in load_actual_plugin
  File "importlib/__init__.py", line 126, in import_module
  File "<frozen importlib._bootstrap>", line 1204, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1176, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1147, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 690, in _load_unlocked
  File "calibre/customize/zipplugin.py", line 205, in exec_module
  File "calibre_plugins.similar_stories.action", line 12, in <module>
    from PyQt4.Qt import QMenu, QToolButton, QApplication, Qt, QMessageBox, QUrl
ModuleNotFoundError: No module named 'PyQt4'
qt.gui.imageio: libpng warning: iCCP: known incorrect sRGB profile
Segmentation fault