Thanks…I am embarrassed to say that I was placing it in the wrong directory.
Next issue: My blog does not have images so when I use the default template in Feed by Mail, the message has an error image placeholder. Would you tell me what part of the PHP code (and which file in which folder) I need to delete in order to get rid of the image it is trying to pull from a post. Thanks very much. I really like the plugin!
Using the ‘show thumbnails’ option did not have an effect.