diff --git a/src/calibre/ebooks/oeb/transforms/rescale.py b/src/calibre/ebooks/oeb/transforms/rescale.py
index d73205709b..e984fad38a 100644
--- a/src/calibre/ebooks/oeb/transforms/rescale.py
+++ b/src/calibre/ebooks/oeb/transforms/rescale.py
@@ -48,6 +48,8 @@ class RescaleImages(object):
                 scaled, new_width, new_height = fit_image(width, height,
                         page_width, page_height)
                 if scaled:
+                    new_width = max(1, new_width)
+                    new_height = max(1, new_height)
                     self.log('Rescaling image from %dx%d to %dx%d'%(
                         width, height, new_width, new_height), item.href)
                     try: