https://portcheckertool.com/image-converter

this fully php based image converter using not extranal library need

this code

<?php
/**
 * Image Converter (All Types)
 * Supported formats: jpg, jpeg, png, gif, webp, bmp
 * Usage: image_converter.php?file=uploads/picture.png&to=jpg
 */

function convertImage($sourcePath, $targetPath, $format)
{
    // Detect file type
    $info = getimagesize($sourcePath);
    if (!$info) {
        die("Invalid image file.");
    }

    $mime = $info['mime'];
    switch ($mime) {
        case 'image/jpeg':
            $image = imagecreatefromjpeg($sourcePath);
            break;
        case 'image/png':
            $image = imagecreatefrompng($sourcePath);
            break;
        case 'image/gif':
            $image = imagecreatefromgif($sourcePath);
            break;
        case 'image/webp':
            $image = imagecreatefromwebp($sourcePath);
            break;
        case 'image/bmp':
        case 'image/x-ms-bmp':
            $image = imagecreatefrombmp($sourcePath);
            break;
        default:
            die("Unsupported source format: $mime");
    }

    // Save in target format
    switch (strtolower($format)) {
        case 'jpg':
        case 'jpeg':
            imagejpeg($image, $targetPath, 90);
            break;
        case 'png':
            imagepng($image, $targetPath, 9);
            break;
        case 'gif':
            imagegif($image, $targetPath);
            break;
        case 'webp':
            imagewebp($image, $targetPath, 90);
            break;
        case 'bmp':
            imagebmp($image, $targetPath);
            break;
        default:
            imagedestroy($image);
            die("Unsupported target format: $format");
    }

    imagedestroy($image);
    return $targetPath;
}

// Example usage via GET
if (isset($_GET['file']) && isset($_GET['to'])) {
    $source = $_GET['file'];
    $format = $_GET['to'];
    $target = pathinfo($source, PATHINFO_FILENAME) . "." . strtolower($format);

    $converted = convertImage($source, $target, $format);

    echo "✅ Image converted successfully!<br>";
    echo "👉 <a href='$converted' target='_blank'>Download $converted</a>";
}
?>



Requirements:

PHP GD extension enabled (php-gd).

Proper file permissions for saving converted images.