Fiji

Fiji is an application based on the ImageJ editor and can handle just about any image you want to analyze and modify.
It can handle TIFF, GIF, JPEG, BMP, DICOM, FITS and RAW formats. With Fiji you are more than capable of processing and editing images in 8-bit, 16-bit and 32-bit form.
As far as interface goes, Fiji is composed from a freely movable toolbar and the windows that contain the opened images. The toolbar provides quick and easy access to all its features and functions which makes it a user-friendly application.
Browsing through the menus there is a big chance that you’ll get overwhelmed with the large number of tools and functions that it allows you to use. Some of them might seem alien-like but they all serve a purpose.
Regardless of your experience with image editing software, Fiji poses no real challenges. Everything is presented to you in a straightforward manner.
Fiji is capable of altering images in the traditional sense but it’s main purpose is to perform a scientific analysis and processing of a photo. It’s designed to offer an in-depth look at the image and treat it as a source for information.
This is why besides standard tools such as ‘Crop’, ‘Scale’, ‘Rename’, ‘Draw’, ‘Sharpen’, ‘Noise’, ‘Shadow’ and others, you get ‘Morphology’, ‘Image Expression Parser’ and such. The tools themselves, no matter how complex and elaborate they sound, are all designed to be easy to use.
A feature that makes Fiji a powerful and versatile tool is the fact that it allows you to install and use a wide range of plugins and since the application is open source, you can very well design your own or have someone create custom ones.
With the above to consider, and a lot more to discover, it’s safe to say that when you want to analyze and process an image, Fiji is the tool to use.