Image to Base64 Converter - Encode Images as Data URIs
Encode an image as a Base64 data URI and copy it as an HTML img tag, a CSS url() value, Markdown, or the raw string. Encoding runs in your browser; nothing is uploaded.
画像をここにドロップまたはクリックしてアップロード
JPG、PNG、GIF、WEBP、SVGをサポート
What Image to Base64 Does
This tool reads your file with the browser's FileReader API and returns it as a data URI: the string `data:image/png;base64,` followed by the file's bytes rewritten in Base64. Base64 is a transport encoding, not a compression scheme. It maps every 3 bytes of binary onto 4 ASCII characters drawn from A-Z, a-z, 0-9, plus and slash, which means the encoded form is always about 33% larger than the file you started with. Nothing about the image itself changes — the pixels, the format, the color profile, and any EXIF metadata all survive untouched, and decoding the string gives you back a byte-identical file. What you gain is a representation made entirely of characters that are safe to paste into source code, which is why data URIs work anywhere a URL is expected: an img src, a CSS url(), a Markdown image, a JSON field. The tool builds those four snippets for you and copies the complete string even when the on-screen preview is truncated, because a data URI for a modest image runs to tens of thousands of characters and rendering all of them would stall the page. Alongside each file it shows the original size, the encoded size, and the overhead percentage, so the cost of inlining is visible before you commit to it. Reading happens entirely on your device; no file is uploaded, and the page keeps working with the network disconnected.
Why You'd Encode an Image as Base64
A data URI turns an image into text, which removes the need for a separate file and a separate HTTP request. That is genuinely useful for small assets and a bad idea for large ones.
How to Convert an Image to Base64
Four steps, all local — the file is read in the browser and the string is built on your device.
Drop in one image or several — each file gets its own card with size figures
Check the encoded size and overhead; under about 10 KB is where inlining tends to pay off
Pick the output you need — raw Base64, an HTML img tag, a CSS url() declaration, or Markdown
Copy the snippet to the clipboard or download it as a .txt file
Frequently Asked Questions
その他の画像ツール
画像編集のニーズに応える他の強力なツールをご覧ください
画像圧縮
サイズ縮小
サイズ変更
寸法変更
画像切り抜き
領域を切り取る
形式変換
形式を変更
フォトエディター
写真を編集
画像回転
画像を回転
画像反転
水平/垂直反転
透かしを追加
透かし
枠線追加
画像枠線を追加
角丸
角丸を追加
フィルター
明るさ/コントラスト
顔をぼかす
顔を隠す
モザイク
領域をぼかす
背景削除
背景を削除
画質向上
AI拡大
テキスト追加
画像にテキストを追加
コラージュ
複数の画像を結合
HTMLから画像
Webを画像に
GIF からシーケンス
フレーム抽出
画像の余白を削除
空白の縁を削除
画像を一括リネーム
ファイル名を安全に一括変更
Circle Crop
Crop images into circles
Black & White
Convert images to grayscale
Split Image
Cut an image into a grid
Merge Images
Combine images into one
Change DPI
Set image DPI metadata