How I Built an AI-Powered Adult (Porn) Content Scanner for Windows (And the Engineering Challenges I Didn't Expect)

Building an AI-Powered Content Scanner for Windows: Performance, Multithreading and GPU Acceleration in .NET Building software always looks straightforward from the outside. You load a machine learning model, point it at some images, and display the results. At least that's what I thought when I started building DetectNix Vision , a Windows desktop application that performs local AI-powered image analysis without uploading user data to the cloud. In reality, the project became a deep dive into performance optimization, memory management, multithreading, GPU acceleration, and user experience. This article covers the engineering challenges I encountered and the architectural decisions I made while building the software from the perspective of a senior developer. The Original Goal The initial goal was simple: Scan images stored on a Windows PC Detect potentially explicit or sensitive content Keep all processing local Support both CPU and GPU execution Process large image collections efficiently Remain responsive while scanning Privacy was a major requirement. I didn't want users uploading personal files to third-party services. Everything needed to run locally on the user's machine. That decision immediately influenced every technical choice that followed. Challenge #1: Model Loading Performance One of the first mistakes I made was loading the AI model too frequently. A modern computer vision model can be hundreds of megabytes in size. Loading it repeatedly creates significant startup overhead and quickly destroys performance. My initial implementation worked perfectly during testing because I was only processing a handful of images. Once I started testing larger image collections, the bottleneck became obvious. The Solution I moved to a singleton-style architecture where the model is loaded once during application startup and remains resident in memory. private readonly InferenceSession _session ; public VisionEngine () { _session = CreateSession (); } This reduced in