So to any of you who may be interested, I've gone ahead and updated my Newgrounds Feed Extension. Don't ask me why this took as long as it did, I did a good 50% of the work just after Newgrounds added support for multi-image posts (kind of) and then just wound up getting distracted before coming back to it today.
But on that note - that's what the update is all about. Now this extension embeds image descriptions into the feed, including any secondary images therein. And to ensure that posts don't wind up overly long, it'll even organise secondary images neatly into two columns where appropriate. It's by no means on par with proper image sets, but I think it does the job quite nicely. And this way you don't have to click through every post to make sure you don't miss anything.