After three days of troubleshooting, I can't help but wonder if there are some specific rules regarding the image_tag function in a Rails environment. The code snippet in my application.html.erb file within the layout directory is as follows. Let's tackle the paths next.
<%=image_tag('./app/assets/images/leaf.jpg')%>
The path to the image is:
app/assets/images/leaf.jpg
The path to the file is:
app/views/layouts/application.html.erb
My hypothesis is that since the views folder is inside the app folder, it needs to navigate out of layouts to access app/assets/images... and beyond.