I recently update to El Capitan ( clean install ) and suddenly facebook is not working on HDPI... The images are not retina ready !! On Safari, Chrome or either on Firefox. The bar, the profile pictures, etc , all is blurry !! just like 3 years ago when the browsers doesn't support retina density. I also try to downgrade to Yosemite but is still crap. Im a photographer and this issue is important to me. I also try: - reseting PRAM and SMT, Checking Fonts, Cleaning all caches etc etc. - donin many clean and no clean Reinstalling. - trying with other facebook acounts, still not working fine. - I try my acount in other machines and its look fine an crispy. - I wrote to Apple, To Facebook and to Mark Zuckerberg ahaha. NO reply yet. Please help me. Thanks !!