diff --git a/src/calibre/ebooks/oeb/polish/container.py b/src/calibre/ebooks/oeb/polish/container.py
index e7dd613b32..aa37c9821c 100644
--- a/src/calibre/ebooks/oeb/polish/container.py
+++ b/src/calibre/ebooks/oeb/polish/container.py
@@ -33,7 +33,6 @@ from calibre.ebooks.metadata.opf3 import (
 from calibre.ebooks.metadata.utils import parse_opf_version
 from calibre.ebooks.mobi import MobiError
 from calibre.ebooks.mobi.reader.headers import MetadataHeader
-from calibre.ebooks.mobi.tweak import set_cover
 from calibre.ebooks.oeb.base import (
     DC11_NS, OEB_DOCS, OEB_STYLES, OPF, OPF2_NS, Manifest, itercsslinks, iterlinks,
     rewrite_links, serialize, urlquote, urlunquote
@@ -1447,6 +1446,7 @@ def do_explode(path, dest):
 
 def opf_to_azw3(opf, outpath, container):
     from calibre.ebooks.conversion.plumber import Plumber, create_oebbook
+    from calibre.ebooks.mobi.tweak import set_cover
 
     class Item(Manifest.Item):
 
diff --git a/src/calibre/library/catalogs/epub_mobi_builder.py b/src/calibre/library/catalogs/epub_mobi_builder.py
index 4aac81765a..b796725f6e 100644
--- a/src/calibre/library/catalogs/epub_mobi_builder.py
+++ b/src/calibre/library/catalogs/epub_mobi_builder.py
@@ -39,7 +39,6 @@ from calibre.utils.date import (
 from calibre.utils.filenames import ascii_text, shorten_components_to
 from calibre.utils.formatter import TemplateFormatter
 from calibre.utils.icu import capitalize, collation_order, sort_key
-from calibre.utils.img import scale_image
 from calibre.utils.localization import get_lang, lang_as_iso639_1
 from calibre.utils.zipfile import ZipFile
 from polyglot.builtins import iteritems
@@ -3890,6 +3889,7 @@ class CatalogBuilder:
          (file): thumb written to /images
          (archive): current thumb archived under cover crc
         """
+        from calibre.utils.img import scale_image
 
         def _open_archive(mode='r'):
             try: