How can you set maximum width for original images?

Question

Case: I have a client that doesn't know much about the digital world. However what she does know is how to get the photo's from her camera on to the computer and in WordPress. However she doesn't know how to downsize the photo's to a normal size.

Solution: I like WordPress to automatically downsize those photo's in the background to a maximum width of 1024px.

Problem: Although I can set maximum width in the settings, I can set the $content_width and I can add new image sizes with 'add_image_size'. The original photo is still stored in the upload-folder in it's original size. Meaning the harddisk space will easily get full.

Question: What should I put in functions.php to let WordPress downsize the original image (if it's larger then the maximum width)?

Answer 1

I was able to solve it using the following code:

function my_handle_upload ( $params )
{
    $filePath = $params['file'];

    if ( (!is_wp_error($params)) && file_exists($filePath) && in_array($params['type'], array('image/png','image/gif','image/jpeg')))
    {
        $quality                        = 90;
        list($largeWidth, $largeHeight) = array( get_option( 'large_size_w' ), get_option( 'large_size_h' ) );
        list($oldWidth, $oldHeight)     = getimagesize( $filePath );
        list($newWidth, $newHeight)     = wp_constrain_dimensions( $oldWidth, $oldHeight, $largeWidth, $largeHeight );

        $resizeImageResult = image_resize( $filePath, $newWidth, $newHeight, false, null, null, $quality);

        unlink( $filePath );

        if ( !is_wp_error( $resizeImageResult ) )
        {
            $newFilePath = $resizeImageResult;
            rename( $newFilePath, $filePath );
        }
        else
        {
            $params = wp_handle_upload_error
            (
                $filePath,
                $resizeImageResult->get_error_message() 
            );
        }
    }

    return $params;
}
add_filter( 'wp_handle_upload', 'my_handle_upload' );

The original file was 3,3Mb after it was uploaded, with large dimensions set to 2048x2048, it took only 375Kb on the server (about 90% reduction!)

Answer 2

Resizing is already done to create the large/medium/thumb sizes, but the problem your facing is that the image is too large to resize, either because of a lack of memory or time.

So resizing isn't an option, if it weren't you wouldn't have your issue. Instead, try limiting the images, so if a 20MB upload happens, it's denied with a message indicating that it needs to be downsized.

Limiting based on image area/megapixels:

<?php
/**
 * Plugin Name: Deny Giant Image Uploads
 * Description: Prevents Uploads of images greater than 3.2MP
 */

function tomjn_deny_giant_images($file){
    $type = explode('/',$file['type']);

    if($type[0] == 'image'){
        list( $width, $height, $imagetype, $hwstring, $mime, $rgb_r_cmyk, $bit ) = getimagesize( $file['tmp_name'] );
        if($width * $height > 3200728){ // I added 100,000 as sometimes there are more rows/columns than visible pixels depending on the format
            $file['error'] = 'This image is too large, resize it prior to uploading, ideally below 3.2MP or 2048x1536';
        }
    }
    return $file;
}
add_filter('wp_handle_upload_prefilter','tomjn_deny_giant_images');

Limiting based on width or height:

https://wordpress.stackexchange.com/posts/67110/revisions

<?php
/** Plugin Name: (#67107) »kaiser« Restrict file upload */

function wpse67107_restrict_upload( $file )
{
    $file_data = getimagesize( $file );
    // Handle cases where we can't get any info:
    if ( ! $file_data )
        return $file;

    list( $width, $height, $type, $hwstring, $mime, $rgb_r_cmyk, $bit ) = $file_data;

    // Add conditions when to abort
    if ( $width > 2048 )
        $file['error'] = 'Error statement';

    return $file;
}
add_filter( 'wp_handle_upload_prefilter', 'wpse67107_restrict_upload' );

Limiting by area would allow tall/thin or wide/short images that can be resized, limiting by dimensions may be easier to explain