How to Efficiently Generate Thumbnails from Uploaded Images in PHP?

Creating a Thumbnail from an Uploaded Image

Generating thumbnails for uploaded images ensures they don't appear distorted while preserving the original image quality. In this question, the user seeks guidance on creating and storing both the original and thumbnail versions of uploaded images.

The user's database setup includes two tables, 'user_pic' and 'user_pic_small', for storing the original and thumbnail versions respectively. The provided PHP code handles the image upload and storage but lacks the logic for thumbnail creation.

Solution using PHP's GD Library:

The solution involves using PHP's GD library to manipulate and generate the thumbnail. A function is defined to take an uploaded image, designated size, and quality as input. It calculates the appropriate dimensions and creates a thumbnail with proportionally sized blackspace to ensure consistency.

Example Usage:

function makeThumbnails($updir, $img, $id)
{
    // Define thumbnail size
    $thumbnail_width = 134;
    $thumbnail_height = 189;
    
    // Calculate dimensions
    // ...
    
    // Check image type and process
    if ($arr_image_details[2] == IMAGETYPE_GIF) {
        $imgt = "ImageGIF";
    } elseif ($arr_image_details[2] == IMAGETYPE_JPEG) {
        $imgt = "ImageJPEG";
    } elseif ($arr_image_details[2] == IMAGETYPE_PNG) {
        $imgt = "ImagePNG";
    }
    
    if ($imgt) {
        // Image manipulation
        // ...
        
        // Output the thumbnail
        $imgt($new_image, "$updir" . $id . '_' . "$thumb_beforeword" . "$img");
    }
}

Solution using Imagick:

This solution leverages the Imagick library, which provides more advanced image processing capabilities. The function generates thumbnails with the specified dimensions and quality, using the Imagick class's built-in methods.

Example Usage:

/**
 * Generate Thumbnail using Imagick class
 */
function generateThumbnail($img, $width, $height, $quality = 90)
{
    if (is_file($img)) {
        $imagick = new Imagick(realpath($img));
        
        // Image processing
        // ...
        
        // Output the thumbnail
        file_put_contents($filename_no_ext . '_thumb' . '.jpg', $imagick);
        return true;
    } else {
        throw new Exception("No valid image provided with {$img}.");
    }
}

Conclusion:

Both solutions offer efficient ways to create a thumbnail from an uploaded image while maintaining its quality. The chosen approach depends on the specific requirements and available resources of the application.

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