diff --git a/src/calibre/ebooks/conversion/plumber.py b/src/calibre/ebooks/conversion/plumber.py
index e027fdbcf9..097729ccef 100644
--- a/src/calibre/ebooks/conversion/plumber.py
+++ b/src/calibre/ebooks/conversion/plumber.py
@@ -135,7 +135,7 @@ OptionRecommendation(name='output_profile',
             choices=[x.short_name for x in output_profiles()],
             help=_('Specify the output profile. The output profile '
                    'tells the conversion system how to optimize the '
-                   'created document for the specified device. In some cases, '
+                   'created document for the specified device (such as by resizing images for the device screen size). In some cases, '
                    'an output profile can be used to optimize the output for a particular device, but this is rarely necessary. '
                    'Choices are:') +
                            ', '.join([x.short_name for x in output_profiles()])