Access uploaded file on $OPENSHIFT_DATA_DIR

I'm not incredibly familiar with openshift yet, so please pardon my noobness haha.

So I uploaded some images to the folder $OPENSHIFT_DATA_DIR/uploaded, but I can't seem to retrieve those files using:

$_ENV['$OPENSHIFT_DATA_DIR'].'uploaded/filename.jpg';

The error message was something like:

The requested URL /var/lib/openshift/xxxxx/app-root/data/thumbnails/filename.jpg was not found on this server.

But when I ssh into my openshift app, the file was there in $OPENSHIFT_DATA_DIR/uploaded/

Is there a particular command to retrieve info from $OPENSHIFT_DATA_DIR?

Thanks!