I like the possibility to use Line Overlay with (bright) renders, (http://www.suplugins.com/help2/line-overlay.php) but the size of your render is limited to the size of your viewport window. (correct me if I'm wrong...) Mostly you want it bigger...
Here's a work-around to get your full-size render and with a nice, fitting Line Overlay:
In this case I want to render to a size of 6000x3000 pixels. My SU viewport has a max. size of 1916x865.
To get a Line Overlay that matches your render, you have to adjust its output size.
SU let's you use a custom size, but only in ratio with your viewport: (again, correct me if I'm wrong...) In this case I choose 6645x3000.
Save your Line Overlay file.
Open the render file and the Line Overlay file in PaintShop Pro, (Photoshop also works) Go to the line overlay, choose 'Select All' and select 'Copy'.
Now go to your render and choose 'Paste as a new layer'
Although your Line Overlay is bigger, the height is the same, in my case the overlay fits perfectly over the render. (the overlap falls outside the frame of the render) I tried this in Ps and it works there also.
Now delete the layer with the render so you have only the trimmed Line Overlay.
Save it under a new name as a PNG.
Now you can give your big render in Podium Image Editor a fitting line overlay....
Here's a cutout with and without lines:
This procedure works nice as long you can choose the same Heigth as your render with a bigger Width. Is your render bigger (see below) it still works, but then you have to clip your render...