This Liferay hook demonstrates how to set up CKEditor to be able to PasteImages og Drag & Drop files right into your Wiki text. This is heavily based on the CKEditor plugin created by Alfonso Martínez de Lizarrondo (amla70@gmail.com)
http://cksource.com/forums/viewtopic.php?t=23646
In this hook, I have included the public version of the plugin, which is somewhat limited. With this version however one can paste images in Firefox and the image gets uploaded as an attachment. However I suggest to pay 15 Euro and buy the license to get et a much better version that will work in Chrome too. It will also handle Drag and Drop of any file.