I'd like include image from system clipboard to comment field. I don't 
want open some image editor, create new image, paste clipboard, save image 
and after that upload it as file.

If it is possible do it at least as import image from clipboard to 
uploaded file with some generated name it will be also great.

Yes, I also find this discussion:

http://stackoverflow.com/questions/6333814/how-does-the-paste-image-from-
clipboard-functionality-work-in-gmail-and-google-c

There is some suggestions in javascript this sound for me promising.
Q:"With HTML 5 features(File Api and the related) - accessing clipboard 
image data is now possible with plain javascript."

But I have no mutch expirience with JS.

Hi Jan

(Sorry for the previous message, it was shortned).
Just wanted to say thanks for the suggestion.

In message
<1385539711.89.0.573172912178.issue2550824@psf.upfronthosting.co.za>
 <1385539711.89.0.573172912178.issue2550824@psf.upfronthosting.co.za>,
Jan Tylich writes:
>If it is possible do it at least as import image from clipboard to 
>uploaded file with some generated name it will be also great.

Maybe this will give somebody an idea. 

This works only for chrome and uses jquery or angularjs
frameworks. Also it does a direct upload to a url as opposed to
posting an entire form from roundup.

https://github.com/Rovak/InlineAttachment

From my reading, firefox may have the underlying support needed to
conde something. Earlier I.E. versions may require flash, active X,
java applet to do this sort of thing.

Also:

  http://joelb.me/blog/2011/code-snippet-accessing-clipboard-images-with-javascript/

has some idea that may be useful as well. It tkes the data as a base64
encoded string and pushes it into the form. So we would need something
to catch the data in roundup and turn it into a real attachment.

Also:

  http://stackoverflow.com/questions/15253468/get-pasted-image-from-clipboard-firefox

  http://stackoverflow.com/questions/2176861/javascript-get-clipboard-data-on-paste-event-cross-browser

https://wiki.roundup-tracker.org/FileUploadViaDragDropAndPaste

outlines what is used on issues.roundup-tracker.org to do drag/drop or paste from clipboard.