TinEye - Reverse Image Search to help find an image's source, duplicates or altered versions.
Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
GImageReader - gImageReader is a simple Gtk/Qt front-end to the Tesseract OCR Engine.
FastStone Capture - A powerful, lightweight, yet full-featured screen capture tool that allows you to easily capture...
Yandex.Images - search for images on the internet, search by image
MWSnap - MWSnap is basically a free to use Windows snapping tools that are used for snapping any part of the screen that is currently displaying on the front of all opened programs and windows.