Small utility that lets you annotate screenshots.
Graphic design and diagram creation software, very popular for its flexibility and powerful features.
Graphic editor that allows you to create, edit, and collaborate on vector design projects.
Software that facilitates batch processing of images, allowing for resizing, converting, editing, and organizing multiple photos at the same time.
Open-source software to handle images with many functionalities.

Program that allows you to create images as if they were painted by hand.