No, if you copy and paste an image into your email it won’t display when you send the message to your subscribers. For the images to render correctly, they have to live online either on your website, or on the system's server. You can also reference the images to an external server. You can upload images during message composition. If you'd like to edit a saved message:
Once the image has been inserted you can right-click on it to access the image properties. We recommend keeping image sizes below 25KB, with the image format set to low resolution (e.g. 72dpi RGB) to decrease the time it takes to load images in the inbox. The higher the resolution, and the wider and longer the image, the bigger the file size. Big images will probably be blocked, and can also take too long to download or render.