Add support for pasting image from clipboard
I often take temporary screenshots of something (eg. to quickly compare something), and have to place that image from clipboard somewhere. Right now I misuse Obfuscate for that, since I can paste an image from clipboard with CTRL+V there. Would be great if I could use Loupe for that. Since it's a temporary screenshot it doesn't need to be saved to disk, means it's fine that it gets deleted once you close the Loupe window.