- PdfDocumentReader: Extract images using PdfPig's GetImages() API
- PowerPointDocumentReader: Extract images from SlidePart.ImageParts
- ExcelDocumentReader: Extract images from DrawingsPart.ImageParts

Common features:
- ImageInfo with Id, Data, MimeType, Position, SourceUrl, Properties
- Magic bytes-based MIME type detection (PNG, JPEG, GIF, BMP, TIFF, WebP, EMF, WMF)
- Minimum size filtering to skip decorative images
- Per-image error handling with warnings