1. Press Print Screen / PrtScn. If you just want to capture the window on top press Alt + Print Screen.
2. Open a graphics program (E.G. Paint) and press Ctrl + V.
3. Using the crop tool, crop your image so only the area you want remains.
4. Save as a .PNG file
5. Upload to Imageshack
6. Right click the link to beside "Direct link to image" and click "Select all", then press Ctrl + C.
7. You can now paste this link wherever you want, and show your image to the world!