I'm not sure where that second picture is from, but I don't think it's legit. It looks edited. I don't think you edited it, but I think the website did. Reason being, a) look at the background. Hyrule Field is never that empty, and b) look at the graphics of Link and Epona. It seems like someone copy and pasted that onto a different background of Hyrule.
ANYWAY, I know what you're thinking, about his hair and all. Maybe it is lighter. But, I think it is in your head. When we see people wearing light clothes (i.e. farm hand's clothes), or in a bright room, their hair appears darker, because of how it contrasts compared to the light around it. And vise versa. When Link is in the green tunic, which is much darker than the clothes he previously wore, his hair appears lighter, because it contrats with the dark green.