We have all been there. Spent time and resources taking the perfect picture, edited it with meticulous precision and then uploaded it on our timeline only to find out Facebook has literally turned it into crap. Not a good feeling (What about my likes maaan?).
A picture can be so important at times, conveying emotions words cannot, showcasing hours of hard work and so much more. It sucks to see our favorite images torn to shreds with artifacts and aberrations that weren’t there just a second ago. Obviously we understand why the compression is being done. Facebook doesn’t charge us for storage and according to the promises it has made, it probably never will.
And we admire that.
But behind the curtains, Facebook is having to pay for storage servers. And judging from the sheer number of photos uploaded to Facebook every minute (about 245,000), Facebook can’t practically make room for all these large file sizes. So compression makes sense. But, the thing is the sort of compression Facebook uses is merciless to say the least. Obliterated gradients and awkward sharpening have long been bothering the sensitive user, not to mention photographers, artists and illustrators.

In order to bypass compression, your files have to be lighter than 100 KB. PNG files presumably go untouched. Hence choosing the “PNG-24” format is a good idea. Especially if the you are uploading is an illustration containing solid colors. Facebook recommends the following widths for pictures on the timeline: 720px, 960px or 2048px.
For Cover photo: 851 x 315.
You also should convert the image profile to sRGB. And make to include as less info in the image file as you possibly can, afterall, it’s just more data facebook will have to compress. If you are using Photoshop, try exporting the image at a quality of 10, instead of going all-out at 12.
There is another option you can try out. There are Photoshop actions you can buy that will prepare your images for Facebook (resize, sharpen etc.). These methods are rather extraneous especially because it’s going to cost you money.
None of the methods above will let you get completely through Facebook’s image processing. Unless Facebook overhauls the processing altogether results will keep disappointing the keen eye. Most people don’t even care, but to those who do, this is a big issue.