Drupal module ImagePicker does not show up in Page edit screen

After installing ImagePicker 6.x-1.2 in a new Drupal site, I opened a book page to try to add images to it. There was no ImagePicker Fieldset below the text entry area. It did show up in “My Account,” though. The Configuration options all seemed correct so I had not changed them. The access permissions were all set correctly – I should have had access.
(Site configuration>ImagePicker)

The solution was to simply open the Configuration Options and save them without any changes.

The direct path to that page is:
http://yoursite.com/admin/settings/imagepicker

Many thanks to maikeru on the Drupal forums for this answer.