If you've ever spent more time writing an Instagram caption than choosing the pics, there's some good news. After years of requests from users, Instagram finally gave carousel posts the upgrade they deserved. The new feature lets you add separate captions to every slide in a carousel post. Now every photo or video in your carousel can come with a proper description. Dropping a concert dump? Add the name of each song in the caption. Posting post-vacay pics? You can mention each location separately, and the caption will appear right under the matching slide. Carousel posts support up to 20...