Photo Extraction & Color Matching

I have several batches of photographs that I will upload manually. My goal is to extract every image from the uploads (they may arrive as simple folders or zipped archives) and then compare them to one another, ranking their similarity purely on overall colour... (Budget: $30 - $250 USD, Jobs: C++ Programming, Data Analysis, Data Visualization, Image Processing, Machine Learning (ML), OpenCV, Python, Software Architecture)