在上传时压缩图像文件大小？ [英] compress image file size on upload?

问题描述

我正在将产品截图上传到我的网站...我想原样上传原始图片并为其创建缩略图，但在上传这两个文件后，创建的缩略图的文件大小比预期的要大一些。有没有办法我可以减少缩略图的文件大小而不影响PHP的质量或使用Imagemagick（我不知道如何使用但我愿意学习，如果需要）...

以下是我用来上传文件的代码..

I am uploading product screenshots to my website... I want to upload the original image as it is and also create a thumbnail for it, but after uploading both the files the filesize of the thumbnail created is a bit larger than expected. Is there any way I could reduce the filesize of the thumbnail without compromising much on the quality in php or by using Imagemagick( which I have no idea how to use but I'm willing to learn if needed)...
Below is the code I'm using to upload my files..

<form action="<?php echo $_server['php-self'];  ?>" 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, 100) ; 

          $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, $save, 100) ; 
        echo "Large image: <img src='images/".$imagepath."'><br>"; 
        echo "Thumbnail: <img src='images/sml_".$imagepath."'>"; 

      }
    } ?>

请指出我的方向正确...谢谢

Kindly point me in the right direction...Thanks

推荐答案

不要传递100作为 imagejpeg的质量（） - 任何超过90的东西通常都是矫枉过正的，只会让你获得更大的JPEG。对于缩略图，请尝试75并向下工作，直到质量/尺寸权衡可以接受。

Don't pass 100 as the quality for imagejpeg() - anything over 90 is generally overkill and just gets you a bigger JPEG. For a thumbnail, try 75 and work downwards until the quality/size tradeoff is acceptable.

//try this
imagejpeg($tn, $save, 75) ; 

这篇关于在上传时压缩图像文件大小？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！