The two-volume set 15725 and 15726 constitutes the refereed proceedings of the 23rd Scandinavian Conference on Image Analysis, SCIA 2025, held in Reykjavik, Iceland, during June 23-25, 2025. The 60 revised full papers presented in these proceedings were carefully reviewed and selected from 98 submissions. The papers are organized in the following topical sections: Part I: Machine learning and deep learning; Segmentation, Grouping, and Shape; Vision for robotics and autonomous vehicles; Biometrics, faces, body gestures and pose; 3D vision from multiview and other sensors; and Vision applications and systems. Part II: Datasets and evaluation; Image and video processing, analysis, and understanding; Detection, recognition, classification, and localization in 2D and/or 3D; Medical, biological, and cell microscopy; Explainable AI for CV; Vision + language (+ other modalities); Computational photography; Fairness; and Low·level and physics·based vision.