Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.
Manual Camera for iPhone - Custom exposure for your iPhone camera
GIMP - GIMP is a multiplatform photo manipulation tool.
Camera Noir - The most powerful black & white photo editor
Affinity Photo - Affinity is the imaging and design suite for creative professionals exclusively for Mac.
Argentum Camera - A monochrome camera with beautiful effects