Base64 から画像コンバータ

// Convert Base64 string to an HTMLImageElement
function base64ToImage(base64String) {
    return new Promise((resolve, reject) => {
        const img = new Image();
        img.onload = () => resolve(img);
        img.onerror = reject;
        img.src = base64String.startsWith('data:') 
            ? base64String 
            : `data:image/png;base64,${base64String}`;
    });
}

// Convert Base64 string to a Blob for download or uploading
function base64ToBlob(base64String, mimeType = 'image/png') {
    const raw = base64String.replace(/^data:[^;]+;base64,/, '');
    const byteCharacters = atob(raw);
    const byteNumbers = new Uint8Array(byteCharacters.length);
    for (let i = 0; i < byteCharacters.length; i++) {
        byteNumbers[i] = byteCharacters.charCodeAt(i);
    }
    return new Blob([byteNumbers], { type: mimeType });
}

const fs = require('fs');

function saveBase64Image(base64String, outputPath) {
    // Strip data URI prefix if present
    const base64Data = base64String.replace(/^data:image\/\w+;base64,/, '');
    const buffer = Buffer.from(base64Data, 'base64');
    fs.writeFileSync(outputPath, buffer);
    console.log(`Saved image to ${outputPath}`);
}

import base64
import re

def base64_to_image(b64_string, output_filename='output.png'):
    # Remove data:image/...;base64, header if present
    data = re.sub('^data:image/.+;base64,', '', b64_string)
    image_bytes = base64.b64decode(data)
    with open(output_filename, 'wb') as f:
        f.write(image_bytes)

# Usage
base64_to_image("iVBORw0KGgo...", "photo.png")

<?php
function base64ToImage($base64String, $outputFile) {
    $data = explode(',', $base64String);
    $binaryData = base64_decode(end($data));
    file_put_contents($outputFile, $binaryData);
}
?>