Medical imaging is critical in detecting and managing infections, with X-ray imaging being a cornerstone in this domain. This review provides an overview of X-ray imaging principles, including the basic mechanisms underlying X-ray absorption and image formation. Emerging trends in X-ray imaging for detecting various infections, such as respiratory infections, bone and joint infections, fungal infections, and viral infections, are discussed in detail. Some advantages of X-ray imaging over other imaging techniques for infection detection are highlighted, along with recent technological advancements in X-ray imaging techniques. Key topics covered include film-screen radiography, computed radiography, flat-panel detector-based radiography, and the evolution of thin-film transistor array-based digital radiography. Additionally, the principles of direct and indirect conversion X-ray detectors are explored, along with primary physical parameters of X-ray imaging such as spatial resolution, contrast, noise, modulation transfer function (MTF), and detective quantum efficiency (DQE). Furthermore, the application of computed tomography (CT) and 3D radiography in infection detection and the role of X-ray microscopy are discussed. Clinical implications of X-ray imaging in infection detection are elaborated, including its role in early detection and diagnosis, assessment of disease progression, identification of complications, guidance for interventional procedures, and screening in high-risk populations. Recommendations for optimizing X-ray imaging in clinical practice for infection detection and suggestions for future research directions are provided. In summary, this review offers insights into the current state and future directions of X-ray imaging for infection detection, highlighting its significance in clinical practice and research. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.