When uploading media, it's important to always upload the best quality file possible.
For images, this means the highest resolution file that you have. The file will be resized on our end so we can deliver the highest quality image depending on the user's device. If you try and upload a 360x160px image, then that image won't look good on higher resolution screens because it will have to stretch to fit the screen since it's that largest resolution we have. So play it safe and upload the largest resolution file you have.