Convert image format PNG to JPEG without saving to disk - PHP

Question

• I am taking a PNG image from a url as below.
• I want to convert the PNG image to JPEG without saving disk with PHP.

• Finally I want to assign JPEG image to $content_jpg variable.

   $url = 'http://www.example.com/image.png';
   $content_png = file_get_contents($url);
  
   $content_jpg=;
  

Diapositive

What do you mean by 'convert the image?' If you want to edit the image, you don't need to save the image, just output it. See: us1.php.net/manual/en/ref.image.php – Showoff

I am doing this in Oxwall. After converting I will save jpg image to system generated location. But I want know the possibility of converting png image content($content_png) to jpg without writing to disk.This is possible whit C# as a tutorial I found. – Diapositive

@Josh, I want to change the format of image from PNG to JPEG. That is what I want to mean by convert the image' and not the edit image. Thanks – Diapositive

@ShankarDamodaran, I will output image to browser. Please let us know if you have any better solution than what we found. Thanks. – Diapositive

Answer 1

You want to use the gd library for this. Here's an example which will take a png image and output a jpeg one. If the image is transparent, the transparency will be rendered as white instead.

<?php

$file = "myimage.png";

$image = imagecreatefrompng($file);
$bg = imagecreatetruecolor(imagesx($image), imagesy($image));

imagefill($bg, 0, 0, imagecolorallocate($bg, 255, 255, 255));
imagealphablending($bg, TRUE);
imagecopy($bg, $image, 0, 0, 0, 0, imagesx($image), imagesy($image));
imagedestroy($image);

header('Content-Type: image/jpeg');

$quality = 50;
imagejpeg($bg);
imagedestroy($bg);

?>

Showoff

The function imagecreatefrompng can accept urls too. So I have passed url to function instead a file. This code work as expected and it out put JPEG file to browser. Thank you very much Josh. – Diapositive

Answer 2

Simplified answer is,

// PNG image url
$url = 'http://www.example.com/image.png';

// Create image from web image url
$image = imagecreatefrompng($url);

// Start output buffer
ob_start(); 

// Convert image
imagejpeg($image, NULL,100);
imagedestroy($image);

// Assign JPEG image content from output buffer
$content_jpg = ob_get_clean();

Diapositive