When to Use Base64 Images
Converting images to Base64 strings lets you embed them directly in HTML, CSS, or JSON without separate file requests. This technique is useful in specific scenarios:
- Small icons and logos (under 2KB): Eliminates an HTTP request. The Base64 overhead (~33% larger) is offset by saving the request latency.
- Email templates: Many email clients block external images. Base64-embedded images display without the user clicking "show images".
- Single-page applications: Bundle tiny images with your JavaScript to avoid additional network requests.
- CSS data URIs: Background images that load with the stylesheet:
background-image: url(data:image/png;base64,...)
When NOT to Use Base64 Images
- Large images: A 100KB image becomes ~133KB in Base64. You lose browser caching, CDN benefits, and lazy loading.
- Multiple images: If the same image appears on many pages, a regular file (cached by the browser) is far more efficient than embedding it in every page's HTML.
- Performance-critical pages: Base64 images increase HTML/CSS file size, which delays initial render.