Facebook showing me Face palm for my photos

From last few days I have been experiencing this horrendous pixelation when I upload photos to my Facebook Photography Page.

The uploaded photos looks C R A P. I usually upload images with the resolution of 2048 to maximum width/height and sometimes with 960 (w/h).

Just a while before I uploaded a nice evening view of Kathmandu Valley to my Facebook Photography Page and below is the before/after.

Photo after some enhancement in Photoshop CS6
Photo after I uploaded to my Facebook Photography Page

If anyone reading this post knows how to overcome this problem please HELP me out.