After getting inspired from Google+ Facebook started showing larger image in web browsers and supports high resolution images upto 2048×2048. Rolling out the same for the Android and iOS web apps, where the users will see the bit larger images instead of showing the tiny image in the news feeds. For example you can check the above image before and after the update of the Faebook app update, but you will see the update as it is not yet rolled out yet and the images are taken from the server side. But we believe that all the users will receive the new update with above features soon.
[Source: The Verge]