I use a simple tool called 'Greenshot', it's freeware and you can take a look in the settings to see how you want it setup. Really easy to change things, but I like the capture region function with an auto save to a folder. This saves the need to crop and save in paint etc.
In terms of uploading and sharing - I store all my images/screens on a GitHub respository. Once again it's free and supposed to be used as code storage/versioning for developers, but I find it good for image uploading
Here is an example (click for full size)...