Googled the web for "edit icons mac" and got a zillion descriptions on how to change the appearance of folders, cut-and-paste wise. I want to bring up an icon in e.g. Photoshop and alter it, mostly the colours. Then save it and use it in Finder & the dock.
I opened the Info panel, selected the icon at the top, copied it and opened in Photoshop. It seems to be 1024 x 1024 pixels. I can edit it. But then, what format is it? I must save it in a format that the Mac can use for Finder icons. Does anyone know?