Another alternative is to use the Snipping Tool, which comes prepackaged with Windows 7. It is hidden away in the following default location:
After running a small test clip, the snipping tool generated a 12 kb image while the Paint/crop method generated a 4 kb image.
Comments do not support the insertion of images. To do that you need to be editing your question (via Ask Question or using the edit button beneath an existing question).
Its the same as for an answer so I'll screenshot this and circle the picture button in red.
To better understand the purpose of comments I recommend reviewing How do comments work? and to ...
The new feature is a consequence of SE responsive design efforts. See Editor improvements for images and links from Meta Stack Exchange:
Adding a link and image in your post is no longer done via pop up dialog. Instead the controls show up inline with the editor. This is sleeker and prepares the way for us to make our desktop theme work across all devices ...
It's still possible, but hidden.
@JoeFriend's answer to Can't upload image from URL anymore:
We no longer have an explicit entry point for this, but you can paste an image link when the uploader UX is showing.
Though at current writing, it might be still buggy for Edge browser.
If using Ubuntu (and probably other Linux distros), you can do partial screenshots easily with Shift+Print Screen. I believe that's the default mapping (I don't recall changing mine and it works for me).
What I frequently do is to export the image with high resolution directly from the software I am working. This is the case with R, ArcMap, QGIS, and other.
When it is not possible to export from a software, I try to improve the image with Photoshop. If it is not possible in Photoshop, I'll print screen zooming the scene as much as possible.
About steps 2 ...