Dlux01053.jpg -

Filenames like "dlux" followed by a number are often internal naming conventions used by specific:

For cataloging product shots (often luxury or "deluxe" items). dlux01053.jpg

To track raw files or proofs from a specific shoot. Filenames like "dlux" followed by a number are

As unique identifiers for digital assets. a specific model

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)?