This plugin will display an image showing the number of comments on a post at the bottom of each feed item (RSS|Atom|etc) that links to the comments section of that post. 
You are able to choose which colors to use for the background of the image and the color of the text as well. 
The reason you would want to use an image instead of plain text is because RSS feeds are generally only updated if the build-date or modification-date components are changed, which does not happen if someone leaves a new comment. This will allow the comment number to update dynamically, regardless of when it’s been first viewed by a user.
You’re able to set the colors of the text and the background in the standard 6 character hex format. 
You may also supply formats for what will show if there are zero comments on your post or more. 
I just added the option to include the image link in the feed excerpts as well. (called by <code>the_excerpt_rss</code> function)
Two Font files are included with the plugin, Arial and SenateBold. You can set which of the two you would like to use, or optionally upload your own .ttf font file to use to render the text on the image.
This requires the GD Image library extension in PHP to function. To check whether or not your server has this use the <code><?php php_info(); ?></code> function and it should be listed.

Feed Comments Number

Add an image that displays the number of comments to your feed items.

bkmacdaddy

Aida B.

leepettijohn

Dee Teal

This plugin allows you to place a widget on your sidebar that fetches the most recent contents of a Pinterest user’s RSS feed and displays the corresponding thumbnail images. You can choose whether to show the description below the image, and you can set the height and width of the thumbnails to fit your theme. You also have the option of showing 4 different sizes of the official “Follow Me On Pinterest” button below the list of your pins.
You can also use this plugin from your theme templates, to display images lists anywhere else on your blog and you can easily give them a fixed size or a maximum size with CSS styling.
Starting with plugin version 1.3, you can also add a list of thumbnails of your Pins to a post or a page in the editor using the shortcode [prw username=”Your Pinterest Username”]. (See FAQs for instructions).
Version 1.4 adds the capability of showing pins from a specific board in the widget or shortcode, rather than just all of the latest pins from a specific user. (See FAQs for instructions).
Note: This plugin is heavily based on the Image Feed Widget plugin created by Yorik van Havre (https://wordpress.org/extend/plugins/image-feed-widget/). As of version 2.0 it also utilizes the jQuery NailThumb script for image resizing (http://www.garralab.com/nailthumb.php) and no longer utilizes the timthumb.php script.

Pinterest RSS Widget

A widget to display thumbnails and titles of the latest Pinterest Pins from a specific user via their Pinterest RSS feed

Feed Comments Number vs Pinterest RSS Widget