Inline images of body is not getting migrated
Looks like the Drupal 6 site which you are wishing to migrate was using the wysiwyg_imageupload module for uploading the images to the content region.
If you have a look at the Repository viewer of the module, you'll see that the module defines certain input filters : Drupal Wiki inline images to be precise which converts the images saved in format [[wysiwyg_imageupload:15:]] into the real path when the page is rendered.

To resolve this, you'll have to implement the prepare function and actually change the value of the content and replace the filter formats with src and then run the migration.