Regenerate Thumbnails Reminder

Plugin Page

A small reminder in your admin area every time a image setting was changed (in media options, through a theme or plugin)

You most likely want to regenerate the thumbnails after this plugin reminds you to do so, if not already done I suggest you install the most used plugin Regenerate Thumbnails for this. This plugin will offer a redirection to Regenerate Thumbnails in the admins reminder notice, but you can use any other plugin/method you prefer to regenerate thumbnails, just click dismiss when the reminder shows up and then manually navigate to your preferred regenerate plugin.