Filenames like "dlux" followed by a number are often internal naming conventions used by specific:
To help you find the original source or the full set of images, could you or describe the subject matter (e.g., a specific model, clothing brand, or car)?
To track raw files or proofs from a specific shoot. dlux01053.jpg
For cataloging product shots (often luxury or "deluxe" items).
Once I have a visual or descriptive context, I can identify the photographer, the brand, or the publication where the full feature appeared. Filenames like "dlux" followed by a number are