Copy-n-Paste: Clipboard Upload Simplified is a lightweight extension for Chromium and Firefox to simplify uploading copied screenshots, images, files from your clipboard. No need to save as files.

Hpaste works/tested for Houdini 21.0 20.5, 20.0, 19.5, 19.0, 18.5, 18.0, 17.5, 17.0, 16.5, 16.0, 15.5. Should work also for 15.0 and maybe even less, to the point ...