Dave Rothgery found this article which may be of interest to PMUG members.
http://www.macworld.com/article/3168524/software-graphics/squash-review-drop-and-compress-your-way-to-smaller-image-files-in-a-flash.html?idg_eid=6a9b303bcbfe97cfd3873b2cd9bb1e5f&email_SHA1_lc=14fb85f0ff8a1a431788e810b911e966194fd8e9&utm_source=Sailthru&utm_medium=email&utm_campaign=Best%20of%20Macworld%20%202017-02-20&utm_term=mw_bestof_html