What is the difference between inline and external images?

Inline images (also called Data URIs or base64-encoded images) embed the entire image data directly in the HTML or CSS using the data: URI scheme. They look like data:image/png;base64,iVBORw0KGgoAAAANSUhEUg... and contain the encoded image bytes.

External images reference separate image files using regular URLs like https://example.com/photo.jpg or relative paths like /images/logo.png.

Inline images characteristics:

  • Reduce HTTP requests (faster initial load for small images)
  • Increase HTML/CSS file size
  • Can't be cached separately
  • Are loaded with the HTML document
  • Ideal for small icons, critical above-the-fold images, or when minimizing requests is crucial

External images characteristics:

  • Stored as separate files and loaded via additional HTTP requests
  • Can be cached independently
  • Don't bloat HTML size
  • Easier to update without changing HTML
  • Better for large images or images shared across pages

For web scraping:

Inline images require decoding the base64 data to get the actual image bytes, while external images need separate HTTP requests to download. Some sites use inline images to make scraping harder or to improve performance for critical UI elements.

Base64 encoding increases data size by about 33% compared to the original image. When extracting images, consider whether you need the raw base64 data or the decoded image bytes.

Our Image Extractor distinguishes between inline and external images and provides options to filter by type.

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