I made a banner for a LinkedIn page in Photoshop, but it turns out the specs are a little off from what the site recommends. I found some specs online that suggest 3270 pixels by 1388, which I used to create the banner, but the site recomments 1128 x 191.
I've tried copy/paste from one to the other, but it copies the artboard as well and makes a mess of things. Is there a quick way to do this or do I need to rebuild from scratch?
Those two image sizes have different aspect ratios - the first is 2.36:1 and the second 5.91:1. With such different shapes you are going to need to do some rebuilding as simply resizing and transforming will make the content appear stretched.