PHP-使用imagepng的脚本不会保存文件，然后显示它

Question

I'm trying to load an image, edit it, save it and then display it from a script that is called within IMG tags. The script works if I want to just display the image and it does save the image. But it won't save it and then display it. Does anyone know what I'm doing wrong? Any help would be greatly appreciated.

<?php
    header('Content-Type: image/png');
    $file_location = "test.png";
    if (file_exists($file_location)) {
        $img_display = @imagecreatefrompng($file_location);

        // This section of code removed as doesn't affect result

        imagepng($img_display, $file_location);
        chmod($file_location, 0777);
        imagepng($img_display);
        imagedestroy($img_display);
    }
?>

Answer 1

Try this and checks if your folder has permission to save the image. chmod 777 on it for sure.

<?php
    header('Content-Type: image/png');
    $file_location = "test.png";
    if (file_exists($file_location)) {
        $img_display = imagecreatefrompng($file_location); // Create PNG image
        $filename = $file_location + time(); // Change the original name
        imagepng($img_display, $filename);   // Saves it with another name
        imagepng($filename);                 // Sends it to the browser
        imagedestroy($img_display);          // Destroy the first image
        imagedestroy($filename);          // Destroy the second image
    } 

Answer 2

Try this:

ob_start();
imagepng($img_display);
$contents = ob_get_clean();
file_put_contents($file_location, $contents);
echo $contents;
imagedestroy($img_display);