[PEPr] Comment on Images::Image_Diff

Is there any compelling reason to make these static methods? Being static means I can't mock them out, and makes them more like namespaced functions than an Image_Diffing object. Ie: Image_Diff::nearlySame() could easily be $diff = new Image_Diff(); $diff->nearlySame(); while having none of the drawbacks of statics (http://misko.hevery.com/code-reviewers-guide/flaw-brittle-global-state-singletons/) -- http://pear.php.net/pepr/pepr-proposal-show.php?id=611