In the past I've tried to set up image pasting before with Lars Tange's
solution
,
but that didn't look how I liked it, as it had a specific field for
pasting attachments.

I am cleaning up some of my former stories and thought I'd do a cusory
search and found this
post by
Christopher Decugis about how he modified it to work. It works great.
Below I'll go over what you need to do if you want this on your portal
as well.

Unfortunately we don't have access to the body tag or the top level div,
so you will have to do this for every page you want it to work on. We
use three forms on our portal, so sc_cat_item, ticket, and form.
You might have more, just be aware you might have to add it for each
page you want to allow it work on.

So on the top level div that is displayed, you need to add
ng-paste="paste($event)" and then in the client script you need to add
the following function;

$scope.paste = function(event){
var files = [];
var clipData = event.originalEvent.clipboardData;
angular.forEach(clipData.items, function(item, key){
if(clipData.items[key].type.match(/image.*/)){
files.push(clipData.items[key].getAsFile());
$scope.attachmentHandler.onFileSelect(files);
}
});
}