What is the best way to delete pages without causing 404 errors?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

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  Marilyn Lesniak: Just wondering. About 1/5 of my images are unattached and not currently in use to to retired and dated posts, updated photos, and indexes that have been updated. Does this affect SEO in any way? I realize they take up space. What is the best way to delete them without causing 404 errors?
  
  Thanks.
  
  +Marilyn Lesniak
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  Edwin Jonk: From the expert panel in this weeks SEO Questions hangout on air on 00:35:08 into the YouTube video: https://dumbseoquestions.com/q/what_is_the_best_way_to_delete_pages_without_causing_404_errors +Marilyn Lesniak
  
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