上传时压缩图像大小-PHP

Question

我正在将屏幕截图上传到我的网站。 我想上传具有相同宽度和高度属性的原始图像，只是我想减小它的大小，例如，如果上传前的图像大小是 3 MB，那么上传/保存后它必须是 300 KB 但在我的情况下，图像是生成的没有显示完全空白的图像。

下面是我用来上传文件的代码..

<form action="" method="post" enctype="multipart/form-data" id="something" class="uniForm">
    <input name="new_image" id="new_image" size="30" type="file" class="fileUpload" />
    <button name="submit" type="submit" class="submitButton">Upload/Resize Image</button>

<?php
    if(isset($_POST['submit'])){
      if (isset ($_FILES['new_image'])){
          $imagename = $_FILES['new_image']['name'];
          $source = $_FILES['new_image']['tmp_name'];
          $target = "images/".$imagename;
          move_uploaded_file($source, $target);

          $imagepath = $imagename;
          $save = "images/" . $imagepath; //This is the new file you saving
          $file = "images/" . $imagepath; //This is the original file

          list($width, $height) = getimagesize($file) ; 


          $tn = imagecreatetruecolor($width, $height) ; 
          $image = imagecreatefromjpeg($file) ; 
          imagecopyresampled($tn, $image, 0, 0, 0, 0, $width, $height, $width, $height) ; 

          imagejpeg($tn, $save, 70) ; 

          $save = "images/sml_" . $imagepath; //This is the new file you saving
          $file = "images/" . $imagepath; //This is the original file

          list($width, $height) = getimagesize($file) ; 

          $modwidth = 130; 

          $diff = $width / $modwidth;

          $modheight = 185; 
          $tn = imagecreatetruecolor($modwidth, $modheight) ; 
          $image = imagecreatefromjpeg($file) ; 
          imagecopyresampled($tn, $image, 0, 0, 0, 0, $modwidth, $modheight, $width, $height) ; 

          imagejpeg($tn, $save, 70) ; 
        echo "Large image: <img src='images/".$imagepath."'><br>"; 
        echo "Thumbnail: <img src='images/sml_".$imagepath."'>"; 

      }
    } ?>

如果我上传 jpg 图像/但不为其他人工作，它工作正常 我想为每种图像类型使用它

Answer 1

对于类型检测，请使用以下代码和说明。

<?php
function imageCreateFromAny($filepath) {
    $type = exif_imagetype($filepath); // [] if you don't have exif you could use getImageSize()
    $allowedTypes = array(
        1,  // [] gif
        2,  // [] jpg
        3,  // [] png
        6   // [] bmp
    );
    if (!in_array($type, $allowedTypes)) {
        return false;
    }
    switch ($type) {
        case 1 :
            $im = imageCreateFromGif($filepath);
        break;
        case 2 :
            $im = imageCreateFromJpeg($filepath);
        break;
        case 3 :
            $im = imageCreateFromPng($filepath);
        break;
        case 6 :
            $im = imageCreateFromBmp($filepath);
        break;
    }   
    return $im; 
}
?>

Answer 2

//This may not be the answer

//in php we have different functions for different image formats so this may helps you
imagecreatefromjpeg ( string $filename )
imagecreatefrompng ( string $filename )
imagecreatefromgif ( string $filename )

imagecreatefromjpeg DOC

imagecreatefrompng DOC

imagecreatefromgif DOC