Chainline isn't a huge issue if it isn't throwing off the chain or causing binding on drive train movement. Yours doesn't look amazing but it if pedals without binding and throwing the chain off then you should be fine. Single speed conversions on wheels that were set up for 5 or 6 gear freewheels generally aren't likely to have a pretty chainline with the wheel centered.

However, you could center the dishing of the wheel and the spacing on the axle.