Something as basic as right click on the image that I see in my browser (Firefox), select 'Set Desktop Background' and be done?

I do not see that option.

What do I do to achieve that?

Ask firefox to add such?

The problem here is the pleathora of linux desktops and no common way to set a wallpaper and probably for plasmashell desktop containments, it's extra-hard (at least there seems no dbus interface, has never been)

iow: you don't. Simply drag the image onto the desktop.

luebking wrote:Ask firefox to add such?

The problem here is the pleathora of linux desktops and no common way to set a wallpaper and probably for plasmashell desktop containments, it's extra-hard (at least there seems no dbus interface, has never been)

iow: you don't. Simply drag the image onto the desktop.

@luebking, I tried doing that. But no use. It creates an icon instead of changing the desktop background.

Same is the effect even if I use Konqueror