You may want copy & paste images just like Microsoft Word - it will be technically pasting from clipboard in your system memory. You can simply do it by adding paste in plugin and paste_as_text=true, paste_as_image=true

<!DOCTYPE html>
<html>
<header>
	<title>TEST</title>
	<link rel="stylesheet" type="text/css" href="/css/content.css"/><header>
	<script src="/js/tinymce/tinymce.min.js" referrerpolicy="origin"></script>
	<script>
			tinymce.init({
			  selector:'textarea',
			  content_style: 'body { font-size: 10pt; font-family: 맑은 고딕체,Calibri,Arial,Sans-serif;; }',
			  plugins: 'nonbreaking autoresize paste',
			  nonbreaking_force_tab: true,
			  forced_root_block: false,
			  autoresize_on_init: false,
			  paste_as_text: true,
			  paste_as_image: true,
			  resize: 'both'
			});
    	});
	</script>
</header>
<body>
<texarea cols=60 rows=10>
Try paste image from your clipboard
</textarea>
</body>

</html>

You may wonder where to store the pasted image, and will found that is pasted as a part of HTML content. It will be something like below:

Try paste image from your clipboard <img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAGoAAABrCAYAAACffRcyAA
AgAElEQVR4Aey9Z3Rc13nvjfuu3Fw7cmznOpZIovdOEGAFO3rH9AEGgzaYwWBm0IhG9MICgp1i7713EL33SlKSbbkkdorjLNuJJbdYsmRbzv9dzz6z
gYMhKEpOPtysZay1tfcpgMDzw9OffcYOf/76H/EE7P5H/JZ//iXxZ1D/Q/4I/gzqz6D+hzyB/yG/pt0Pf/hD/Hn8v/8M7MZnJrDYmJidhHgsdo/4nP
jexdaTT6dAg1/jx+Jz/BrN4uuvWk89m37l/XSPeEw/ncHUU+Hc7NNpPHs2jW9+65sYGhlDRWUlrt27j4c9veiemMKxqzfx5tnzMJrzUVRWgtC1qxAU
FIDo6Dg07N8PfV4eZKo0HL/3GH3T30Dp9hqk5xbj6oNWjE6PY3RsAIOjgxgaHcLI6DCbaT38OcZLQYkhfJa1+CG/ai1+8C+7V3zPf8daDImtnwpwCd
bM81mMTk3gzp1baKyvxbEzZ3Hl3iPsO34K+0+eRvORkzh0+gwqG3eiYd9BFJdtR0FVDUprGqBKz0B6ugZytRKNJ47iWlsHWo4dh0ythqm0AmfuPMLD
ngEMjI1ieGyYwSFInxvU2PQ4FhufBc6fcs/LwHze8/8d8GaezuDZ82foGR7EmcuXsW9vMxobqnHi0iU0tbTAZDZCKktCdFQUwiO2QiKTIk4qQVRUFG
QpSmSYc5FuMiLdkAejJR/GbcUoqq5FbnEJZColdEWlOHWvHTefdKG1qwOjEyP/dVC2D30xeOJztvfbPmjb67bHtvfbHr8KBN3/qnvE120liq4RqMGh
.....
AHW9vc94djm9yWh3TQ8Ljw8Mpjww928e3WFt65eRtf3d3GwcM9fHN3G8unL6M3OIumv4pGZ4BiqYyy58G1SLayvTgFR0/B0ZJiUewl54MzMlRvE7Ao
VeRUdmeyRtKpLemwdA1OXhfX6Zg6rLwJw13G9EwNMzNZ6EYVTmUJea+NTDqHdCqBTCot04p6jglJEmyLtvWU/D+R5KUHIw7T5JxVAo6Zgsf03NVRrZ
VQqXmozM+h3uZkSV0Si+qwj4JKMAth7qQ58tNPP+H/63//GfwbkzHbL6z9XW8AAAAASUVORK5CYII=" /><br /><br />