Not So round Sun?

I measured the equatorial diameter and polar diameter of the sun in this photograph, the former seemed to be 1% more than the later. 
It is likely optical delusion because in actual fact, the polar diameter is only 10km less than equatorial diameter of almost 696,342km.
Firstly, it rotates slowly, each round at 28 days. Secondly, it is not affected by gravities of other planets, too small and too far away to have much effect.