I just found this cool app one day on etsy and thought I would share it with you! It's an app on the website called Craftopolis, and it allows you to edit all of your listings at once. Pretty amazing stuff if you ask me! Here, I'll walk you through it.
So, first, go to Etsy and on Your main Etsy page, scroll down to the last link on the menu at the left, called Featured Apps.
This link will take you to a list of all kinds of cool Etsy apps, but amongst the list, find Craftopolis.
But you can also edit listings descriptions, and titles too! I haven't found something this easy in a long time- I love that you can do it all at once. Now if they would allow you to change and store your banners here too, I'd be all set!