No matter what you try, you cannot change the banner image of your company when you try to do so on your company’s Linkedin page.
When you click on “Add image” while editing your page, a popup can be seen which says:
“PNG, JPEG, or GIF; max size 2 MB. Image must be 646 x 220 pixels or larger.
Note: You can crop your image once it’s uploaded.”
Make sure you choose the image correctly because if you choose an image which you wish to change later on then it won’t let you do so.
Here is a post written by Jo Shaer about it in 2014:
It is 2016 and the issue still remains the same.
If you try to add another image, you will be able to see the same image which you initially uploaded. If you change browser and try to do this, even then you will get the same result. If you choose a third browser and remove the image and then try to add another image, you will still get the same image which you first uploaded.
Update: Did not work even after clearing entire history and cache.
Please mention in comments section if you face the same issue or have been able to solve it somehow.