There are five core categories of multimedia that can be used in multimedia systems: text, images, audio, video, and animation. Text is the most common media and is crucial for conveying information. Images are often used for buttons and other interactive elements. Audio provides a link between text and images, while common formats are MP3, WMA, and RealAudio. Video can be streamed or downloaded and uses formats like Flash, MPEG, AVI, WMV, and QuickTime. Animation engages users and is often created with Adobe Flash.