Base64 Images: When and How to Use Them
Understanding Base64 image encoding for web development.
Base64 encoding converts binary image data into a text string that can be embedded directly in HTML, CSS, or JavaScript. This eliminates the need for a separate image file and HTTP request.
How Base64 Works
Base64 encoding represents binary data using 64 ASCII characters (A-Z, a-z, 0-9, +, /). Every 3 bytes of binary data become 4 characters of Base64 text. This means Base64 encoded data is about 33% larger than the original binary.
When to Use Base64
Small Images and Icons
For images under 2-3 KB, the overhead of an HTTP request often exceeds the cost of the larger Base64 string. Embedding small icons and decorative elements as Base64 can improve performance.
Single-File Documents
When you need everything in one HTML file (email templates, exported reports, offline documents), Base64 images eliminate external dependencies.
CSS Background Images
Small background patterns and UI elements can be embedded directly in CSS files, reducing HTTP requests.
When Not to Use Base64
Do not Base64 encode large images. The 33% size increase plus the inability to cache separately makes this counterproductive for anything over a few kilobytes.
Do not use Base64 for images that appear on multiple pages. A regular image file can be cached once and reused, while Base64 data must be downloaded with every page.
Our Tool
Use our Image to Base64 converter to quickly encode images. It provides both the raw Base64 string and a ready-to-use img tag that you can paste directly into your HTML.
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