gruntjs/grunt-contrib-imagemin — pull request #53 by phpmycoder (2013-08-09 22:15:28+00:00)
Title: Made PNG and JPG extensions case insensitive

Although it's an ugly practice (and I much prefect `.png` and `.jpg`), the case of these image extensions is irrelevant. `.png` and `.PNG` are synonymous. Originally, imagemin only compressed images with lowercase extensions. I've added two lines (and some tests) so that images with uppercase extensions aren't ignored.