What is Base64 Encoding?
Base64 is a binary-to-text encoding scheme that represents binary data in a string format using 64 different ASCII characters. It converts any binary data (including images) into a text string that can be safely transmitted over text-only protocols like email or embedded in HTML/CSS. This is particularly useful for web development and data transmission.
Why Use Base64 for Images?
- Inline Images: Embed images directly in HTML/CSS without separate files
- Email Safety: Include images in emails without external links
- Database Storage: Store images as text in databases
- Single File Delivery: One HTML file contains everything needed
- Reduced Requests: Fewer HTTP requests improve performance
How to Use Base64 Images
In HTML: Use <img src="data:image/png;base64,..." /> In CSS: Use background: url('data:image/png;base64,...'). The data URI format starts with "data:", followed by MIME type, encoding method (base64), then the actual encoded data. This allows browsers to display images without fetching external files.
Pros and Cons
Advantages: Self-contained files, works offline, reduces HTTP requests. Disadvantages: Larger file sizes (30% bigger than binary), not cacheable separately, difficult to modify. Use Base64 for small images, icons, or when you need self-contained files. For large images or better caching, use traditional image files.
Size Considerations
Base64 encoding increases file size by approximately 33%. A 10KB image becomes ~13.3KB in Base64. For performance-critical applications, consider the trade-off between self-contained files and bandwidth usage. Modern bundlers often optimize this automatically.