StreamingAssets -only visible in editor, not after build

Defining the path to dynamic image assets like so

tempStr =“file://”+ Application.streamingAssetsPath + “/foo.png”;

And using the WWW class.

In the editor the images load correctly. But after building, the images don’t seem to load.
I checked the package contents in OSX, and the images ARE there in

Content>Resources>Data>StreamingAssets

What gives?

try file:///