Create Thunderbird Plugin to change RSS output -- 2

I am looking for a talented Thunderbird Plugin developer to create a small plugin to optimize my RSS reading. My current RSS feeds in Thunderbird output the normal way, some feeds have an image. Most image providers have two links, one for a thumbnail, one for the full image. RSS feed usually use the thumbnails. But I want to see the full image as output in Thunderbird view. The plugin should be able to change the content field text if it encounters a certain link. I was able to find a Tiny Tiny RSS php script (attached) doing what I want but I am lacking the ability to convert it into a Thunderbird plugin. The plugin should have 3 editable variables, 1 for finding the correct link (as different feeds use different image hosters or change hosters from time to time), 1 for the text to be replace and 1 for the replacement.