rails routing without slash separator

I'm not sure I understand what you mean here.

what's stopping you from putting the images in the
railsapp/public/images directory? There's nothing saying you MUST use
<%= image_tag ... -%>, you can use the standard html tag and skip the
rails method.

<img src="/images/..." />

not sure what you mean by "different path lengths" and "you can't use
standard relative urls for images"

please explain further.