I've been using your plugin for several months. Thank-you it worked for me when nothing else would. I have an ebook site and I use WP-robot to populate the posts, then I publish the feed in an RSS to email newsletter. I like to include the images in my posts, but it doesn't make it a featured image. Fortunately, your plugin puts the image in the feed and my newsletter looks great.
The new update broke my feed in MailChimp and the images stopped showing, then the feed broke altogether. Then I tried disabling your plugin and installing some others and ended up breaking my site. No matter what I tried I couldn't get it fixed. Finally had to have my host restore a full backup to get things working again.
The old version of your plugin was in the old backup so everything is working again. I just have to make sure and not accidently update it. The error I got was the extra line error too. It might have something to do with pulling featured images instead of first images. Good luck.