Images, Audio, Video & Web Delivery
Digital media must be stored in a format, compressed when appropriate, and delivered in a way that the user's device can understand.
File Formats and Compression
A media file format defines how information is organized so software can store, open, edit, or play it. Common examples include JPEG, PNG, GIF, WebP, and SVG for images; MP3, AAC, WAV, and FLAC for audio; and MP4 or WebM containers for video.
Compression reduces the amount of storage space or network bandwidth needed for media. Lossless compression attempts to preserve the original information, while lossy compression reduces file size by discarding some information. The best choice depends on whether the priority is maximum quality, small file size, editing flexibility, or fast delivery.
Audio and Video Delivery
MDN explains that web audio and video can be delivered as ordinary media files or through streaming technologies, and browsers use HTML media elements and related APIs to manage playback. (MDN, 2026)
Responsive Images
Images that look good on a laptop may be unnecessarily large for a phone. Responsive-image techniques allow a website to provide image resources that are appropriate for different screen sizes and resolutions, which can improve performance across devices. (MDN, 2025)
Accessibility
Multimedia should also be usable by people with different needs. Captions and subtitles help users understand spoken content when audio is unavailable or difficult to hear. Alternative text helps describe meaningful images. Clear controls, readable text, and avoiding unnecessary autoplay can also improve usability.