Using Firefox 23 beta I am unable to load a Flickr set (see URL). Firebug shows me:

Blocked loading mixed active content "http://api.flickr.com/services/rest/?&nojsoncallback=1&method=flickr.photos.licenses.getInfo&api_key=...&format=json"

https://bits.wikimedia.org/commons.wikimedia.org/load.php?debug=false&lang=de&modules=ext.centralNotice.bannerController%7Cext.uls.displaysettings%2Cime%2Cinit%2Cinputsettings%2Cinterface%2Clanguagenames%2Clanguagesettings%2Cpreferences%2Cwebfonts%7Cext.uls.webfonts.repository%7Cjquery.client%2Ccookie%2CdelayedBind%2Ci18n%2Cime%2CjStorage%2Cjson%2CmwExtension%2Ctipsy%2Culs%2Cwebfonts%7Cjquery.uls.data%2Cgrid%7Cmediawiki.Uri%2Capi%2Ccldr%2CjqueryMsg%2Clanguage%2Cnotify%2Cuser%2Cutil%7Cmediawiki.api.parse%7Cmediawiki.language.data%2Cinit%7Cmediawiki.legacy.ajax%2Cwikibits%7Cmediawiki.libs.pluralruleparser%7Cmediawiki.page.startup%7Cskins.vector.js&skin=vector&version=20130715T203802Z&*
Line 83

Version: unspecified
Severity: normal
URL: https://secure.flickr.com/photos/larssteffens/sets/72157634628481376/