如何允许用户下载图片（.gif，.png，.jpeg）？

Question

How can I allow users to download pictures saved on the server? The goal is to have the user click on a link and have a specified image to start to download.

Facebook example:

Answer 1

Make the link to another .php page, not the image. Then on that page use the content-disposition header like this:

<?php
// Define the name of image after downloaded  
header('Content-Disposition: attachment; filename="file.jpg"');  

// Read the original image file  
readfile('file.jpg');  
?>  

From there, you can just add the filename of the image in a get command like

`download.php?filename=file` 

then reference that in the file as:

readfile($_GET['filename'].'.jpg')

Answer 2

You need to set a specific header on the response that delivers the image in order to force a download.

Content-Disposition: attachment; filename=myawesomefilename.png

Otherwise it will just load up in browser.

So send that header and then just link to the path that delivers that image with that header.

Answer 3

Send a header to tell the browser to download it like this:

header("Content-type: application/force-download")

Then send them the data for the file itself without any HTML or anything.

This example is snipped from the PHP docs

<?php
$file = 'monkey.gif';

if (file_exists($file)) {
    header('Content-Description: File Transfer');
    header('Content-Type: application/octet-stream');
    header('Content-Disposition: attachment; filename='.basename($file));
    header('Content-Transfer-Encoding: binary');
    header('Expires: 0');
    header('Cache-Control: must-revalidate');
    header('Pragma: public');
    header('Content-Length: ' . filesize($file));
    ob_clean();
    flush();
    readfile($file);
    exit;
}
?>

Answer 4

If by "download pictures saved on the server" you mean "try to make the browser offer a 'save as' dialog box instead of just displaying the image" then you might want to look into using the Content-Disposition: attachment header in the response that serves the image:

Content-Disposition: attachment; filename="thefilename.jpg"

You can set headers in php using the header function .