image.go: Improve help about aliases and remotes
image.go: Improve help about aliases and remotes

Signed-off-by: anatoly techtonik <657222fa4408d5fb9c49497617f580f8c5974a3b@gmail.com>
georghopp/lxd,beni55/lxd,atxwebs/lxd,stgraber/lxd,dustinkirkland/lxd,achanda/lxd,akshaykarle/lxd,yura-pakhuchiy/lxd,jensg-st/lxd,Skarlso/lxd,atxwebs/lxd,stgraber/lxd,ericsnowcurrently/lxd,pcdummy/lxd,mikemccracken/lxd,jsavikko/lxd,Skarlso/lxd,erikmack/lxd,Malizor/lxd,erikmack/lxd,stgraber/lxd,akshaykarle/lxd,hallyn/lxd,jensg-st/lxd,jumpstarter-io/lxd,chrisglass/lxd,jsavikko/lxd,mikemccracken/lxd,ollie314/lxd,dustinkirkland/lxd,pcdummy/lxd,stgraber/lxd,smoser/lxd,mikemccracken/lxd,beni55/lxd,lxc/lxd,lxc/lxd,hallyn/lxd,beni55/lxd,mjeanson/lxd,pcdummy/lxd,Malizor/lxd,techtonik/lxd,yura-pakhuchiy/lxd,jensg-st/lxd,smoser/lxd,hallyn/lxd,dustinkirkland/lxd,stgraber/lxd,lxc/lxd,erikmack/lxd,Skarlso/lxd,georghopp/lxd,jsavikko/lxd,jumpstarter-io/lxd,hallyn/lxd,georghopp/lxd,ollie314/lxd,ericsnowcurrently/lxd,chrisglass/lxd,benaryorg/lxd,hallyn/lxd,lxc/lxd,atxwebs/lxd,smoser/lxd,achanda/lxd,benaryorg/lxd,techtonik/lxd,achanda/lxd,Malizor/lxd,atxwebs/lxd,lxc/lxd,mjeanson/lxd,stgraber/lxd,stgraber/lxd,jumpstarter-io/lxd,ericsnowcurrently/lxd,yura-pakhuchiy/lxd,hallyn/lxd,ollie314/lxd,chrisglass/lxd,mjeanson/lxd,akshaykarle/lxd,techtonik/lxd,benaryorg/lxd,lxc/lxd,Skarlso/lxd,lxc/lxd