Base64 Tutorial: Text and Images
Enter text in the first box and choose Encode. For example, Hello becomes SGVsbG8=. Paste SGVsbG8= into the first box and choose Decode to get Hello.
Choose one image using the file picker. Your browser reads it and displays a Data URL in the result box. Copy the full result, including the data:image/...;base64, prefix.
Use a complete image Data URL in an HTML img src attribute or a CSS url() value. Example: <img src="data:image/png;base64,..." alt="Description">. Replace the dots with actual image data; email clients may restrict Data URLs.
Base64 is encoding, not encryption. Its size is approximately one third larger than the original binary data, before any Data URL prefix. Large images may slow the browser; use ordinary image files when appropriate.