Not sure about your OS, but on Ubuntu and many Linux distributions you can press Ctrl+Shift+PrtScrn to select a region of your screen to screenshot and copy it

Not sure about your OS, but on Ubuntu and many Linux distributions you can press Ctrl+Shift+PrtScrn to select a region of your screen to screenshot and copy it to your clipboard. I commonly use a workflow of Ctrl+Shift+PrntScrn, select a region, then Ctrl+V to paste the screenshot where I need it - really low friction, and surprisingly many websites support pasting images. (I suppose other OS's have similar shortcuts as well, so if you use something else, this might be worth Googling for.) Otherwise, I think Pocket might be exactly scrapbook-collector-type thing you're looking for?