Copy a file from the desktop and paste it in the contentEditable element and/or the input. If you paste an image and can be read, it will be shown in the output.
Extra info available in the console

Paste a file here

Firefox allows pasting both on the input and the div, and taking as source a file from the desktop or an image from the clipboard

Chrome: https://bugs.chromium.org/p/chromium/issues/detail?id=316472
It works in MacOs: https://bugs.chromium.org/p/chromium/issues/detail?id=361145

Edge: https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/11848601/

Safari. There's a file in the data, but it can't be read. https://bugs.webkit.org/show_bug.cgi?id=171504