If an eBay reseller posted that particular picture, then he's simply lying -- as noted at the site where that picture was posted, it was taken at the Apple distributor at KLCC in Kuala Lumpur.
There are various ways to get stock of items like that, including just buying them outright close to retail and selling them as a loss leader. No magic wholesale secret required; you sell the super hot item at a decent price as a means to acquire customers to whom you then upsell other items. It can require significant outlay to do something like that, but over the course of the exercise you've built a customer list of proven buyers who've had a positive experience with you, which is an invaluable marketing tool; and if you balance funds and stock correctly, you can do so with minimal net outlay once the stock has been sold and rotated.
One of my closest friends who sells on eBay has been doing this for years. His secret mega wholesale source is the Best Buy down the road from where he lives, where he just takes advantage of all sales, closeouts and coupons that he can to always have top brand stuff at a competitive price.