Default view format / fleximage

I’ve been having a problem of late with view formats. I am using the
FlexImage plugin to provide thumbnailing which adds its own view
tempaltes.

I would usually access a my resource via

http://localhost:3000/photos/1

Since photo is my model I would normally see the rendered
app/views/photos/show.html.erb
instead I am getting
app/views/photos/show.jpg.flexi

I am just wondering, is the view that is used defaulted to the first
alphabetically. Its very confusing I assumed that the format is
defaulted to html somewhere unless otherwise specified. If that is the
case in development I am getting the html view displayed, but in
production it defaults to jpg which is crazy. It seems to inconsistently
switch between the two.

Does this ring any bells with anyone?

RobL