Exporting for Social Media

Could someone help me determine how to export all my photos for the web and/or social media? For example, let's say I want to export 15 images for Facebook and Instagram. It's recommended that I export the long edge for landscapes and the short edge for portraits. But what if there is a combination of landscape and portraits in the images? Do I only select all the landscapes and export with the long edge and then separately export all the portraits on the short edge? Or can I export them all at the same time so the images are in the order I want them to be in? 

I greatly appreciate any help. Thank you in advance.