How can one troubleshoot the "supplied argument is not a valid Image resource" error in PHP when using imagecopyresampled?

When encountering the "supplied argument is not a valid Image resource" error in PHP while using imagecopyresampled, it typically means that the image resources being passed to the function are not valid. To solve this issue, ensure that the images are properly loaded using functions like imagecreatefromjpeg, imagecreatefrompng, or imagecreatefromgif before using imagecopyresampled. 

// Example code snippet to fix "supplied argument is not a valid Image resource" error
$sourceImage = imagecreatefromjpeg('source.jpg');
$destinationImage = imagecreatefromjpeg('destination.jpg');

// Check if images were loaded successfully
if($sourceImage && $destinationImage) {
    // Perform imagecopyresampled operation
    imagecopyresampled($destinationImage, $sourceImage, 0, 0, 0, 0, imagesx($destinationImage), imagesy($destinationImage), imagesx($sourceImage), imagesy($sourceImage));

    // Output or save the resulting image
    imagejpeg($destinationImage, 'output.jpg');
} else {
    echo 'Error loading images.';
}

Keywords

imagecopyresampled PHP error troubleshooting Image resource

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