Question 1

Why convert an image to Base64?

Accepted Answer

Base64-encoded images can be embedded directly in HTML, CSS, or JSON as a data URI, eliminating the need for a separate HTTP request. This is useful for small icons, email templates, and offline-capable web apps.

Question 2

Does converting an image to Base64 change its quality?

Accepted Answer

No. Base64 encoding is lossless — it is just a different way to represent the same binary data. The image quality and file content are identical; only the representation changes.

Question 3

Why does Base64 make the file about 33% larger?

Accepted Answer

Base64 encodes every 3 bytes of binary data into 4 ASCII characters. This overhead of 4/3 × original size explains the ~33% size increase. For large images, a direct file reference via URL is more efficient than Base64 data URIs.

画像からBase64データURIへ

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