This works for me: Assign a Material to the inserted image, as outlined below. Render in LightWorks Smooth OpenGL mode with "Nonrenderable objects" enabled.
Material Pattern = "Wrapped filtered image." Do NOT navigate to a specific file. Leave the other Pattern parameters at the default values.
Reflectance = "Constant," with Brightness = 1.0 for starters.
Transparency = "Plain coverage," with Coverage = 0.6 for starters.
Texture and Wrapping = "None."