1. Flatten the image by taking a screen capture of the content;
2. Paste it in an image editor;
3. Crop to size;
4. Upload

This would be the direct/I-have-access-to-an-image-editor way. However, ...

The StackExchange image hosting service IMGUR also allows "online cropping of images".

1. Flatten the image by taking a screen capture of the content;
2. Visit [IMGUR](http://www.imgur.com) and click on Web (or on the Upload button in the top "menu" bar)

 ![enter image description here][1]

3. Paste your screen shot from your clipboard (<kbd>Ctrl</kbd>+<kbd>V</kbd>; you may have to click on that part of the dialog box):

 ![enter image description here][2]


4. Check the "Edit" box and hit the "Start Upload" button:

 ![enter image description here][3]

 ![enter image description here][4]

5. Crop to your liking and save

 ![enter image description here][5]

6. Copy the "Direct Link URL" and upload the result using the regular StackExchange image upload service, this time "from the web". This follows that same procedure listed in [How can I upload an image to be included in a question or answer?](http://meta.tex.stackexchange.com/q/2136/5764):

 ![enter image description here][6]

 ![enter image description here][7]

7. Done

 ![enter image description here][8]

It's advised to re-upload the image from IMGUR's default site to the dedicated StackExchange IMGUR hosting service, otherwise the link might turn up dead later. Once you get used to this as an alternative, it's not that complicated.


  [1]: https://i.sstatic.net/U5nx9.png
  [2]: https://i.sstatic.net/B3CEZ.png
  [3]: https://i.sstatic.net/ovVt1.png
  [4]: https://i.sstatic.net/Qgoaw.png
  [5]: https://i.sstatic.net/Sku6l.png
  [6]: https://i.sstatic.net/rN62C.png
  [7]: https://i.sstatic.net/QaYtR.png
  [8]: https://i.sstatic.net/fibUl.png