Is it possible to create an xml file (rss) from a folder of images?

[Ghoulish Delight]

An RSS/xml file will not actually contain the images, just links to the images (RSS/xml is just formatted text, nothing else). So without spending the time to actually upload the files to your WP site, it's not going to work.

If you have access to the server the site is hosted on, you could upload all of the images directly, then create an RSS file with the image location data. This is where Excel (and a tool like this one) could be helpful. Just add the info for each post, including an img link to each photo that you uploaded to the server, create the RSS file (which is nothing more than an XML file that follows some standards) and you'd be ready to import it into Wordpress.

But depending on how much sense that all made to you, it may be less work to just go ahead and grind through manually creating the posts.