Raster graphics are images captured using scanners and consist of bitmap files like BMP, TIFF, GIF and JPEG. They have larger file sizes than vector graphics. Vector graphics can be edited without losing resolution and are smaller file sizes. Common file formats discussed include JPEG for photos, TIFF for publishing, GIF for animations, BMP for bitmaps, PSD for Photoshop, AI for illustrations, FLA for animations/games, and WMF for logos on Windows. Compression reduces file sizes but also image quality. Scanners, cameras and graphics tablets capture images digitally. Optimizing improves quality through resizing and compression while storage is improved using descriptive names and organized folders.