Image Resizing Magic: How to Resize on Upload with PHP

Hey there! So you’re looking for a way to Image Resizing automatically when users upload them to your website? Smart thinking! Resizing images on upload can be super beneficial for a few reasons:

Saves Storage Space – Full-size images from cameras and smartphones can be HUGE. By resizing to a smaller size on upload, you massively cut down the storage space needed.

Faster Page Loads – Smaller image files means faster downloads and smoother page loads. Users hate waiting around for giant images to load.

Consistent Sizing – You can standardize the size of images in your content. No more mix of wonky small and massive images.

Performance Gains – Processing smaller images puts less strain on your server resources.

So resizing during upload is really a win-win for both you and your users! Before starting here is our precious article:

Using a PHP Script to Resize on Upload

PHP is a great server-side language for handling uploads and resizing images. And the best part – PHP is free!

Here’s a step-by-step for the PHP image resize process:

  1. Check and validate the uploaded file
  2. Get the image type and extension
  3. Load the image using a PHP image create function
  4. Get the original width and height
  5. Define the new resized dimensions
  6. Create a new image at the new size
  7. Use imagecopyresampled() to resize and copy over the original
  8. Save the resized image to a new file
  9. Free up memory used in the process

That’s the gist of it! With those steps, the uploaded image is resized to your new dimensions before it even hits your server storage.

Image Resizing

Handy Features to Add

Some handy extras you could add to your PHP image resizing script:

  • File type checking – only resize valid image types
  • Output quality setting – balance quality and file size
  • Error handling – deal gracefully with any errors
  • Security checks – protect against exploits
  • Easy config – set dimensions, quality, etc. from a config file
  • Watermarking – add a watermark during resizing
  • Thumbnail creation – generate a smaller thumbnail copy

The possibilities are endless! A simple PHP script can turn into a sophisticated image management system.

Where to Get the Code

If you don’t want to code from scratch, there are lots of open source PHP image resize scripts out there. Just Google “PHP image resize script” or search GitHub.

Image Resizing-php code

Or check out this free script I found that should do exactly what you need:


// Set the path to the upload directory
$uploadDir = '/path/to/uploads/'; 

// Get the filename
$filename = $_FILES['file']['name'];

// Get the file extension 
$extension = pathinfo($filename, PATHINFO_EXTENSION);

// The resized filename
$resizedFile = $uploadDir . 'resized_' . $filename; 

// Allowed extensions
$allowedExts = array('jpg', 'jpeg', 'png'); 

// Validate upload
if ((($_FILES['file']['type'] == 'image/jpeg') || ($_FILES['file']['type'] == 'image/jpg') || ($_FILES['file']['type'] == 'image/png'))
&& in_array($extension, $allowedExts)) {

  // Load the image
  $image = imagecreatefromjpeg($_FILES['file']['tmp_name']);

  // Get original dimensions
  list($width, $height) = getimagesize($_FILES['file']['tmp_name']);

  // New dimensions
  $new_width = 320;
  $new_height = 240;

  // Resize
  $resizedImage = imagecreatetruecolor($new_width, $new_height);
  imagecopyresampled($resizedImage, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);

  // Save resized image
  imagejpeg($resizedImage, $resizedFile, 90);

  // Free memory



Customize it to your needs, drop it on your server, and you’ve got automatic image resizing on upload!

This script checks the uploaded file type, loads the image, gets the dimensions, calculates new resized dimensions, creates a new image, resamples and copies pixels to resize the image, saves the resized image, and frees memory.

The key functions are:

  • imagecreatefromjpeg() – load image from file
  • list() – get image dimensions
  • imagecreatetruecolor() – create new image
  • imagecopyresampled() – resize and copy image
  • imagejpeg() – save resized image

You can set the resized width and height and quality as needed. Add validation, security checks, error handling etc. as per your requirements.

Any Questions about Image Resizing?

That’s a quick overview of using a PHP script to resize images during the upload process. Let me know if you have any other questions! I’m happy to chat more about image handling, web performance, or any other web development topics.

Hope this gives you what need to get started resizing those images like a pro. Happy coding!

Also Read: The Rise of Smart Earbuds: Integration with Devices


  1. What image formats should I use when images resizing?

The best image formats for resized images are JPG for photos, PNG for logos and illustrations, and WebP for maximum compression. GIF can be used for simple images with animation.

  1. How can I resize images without losing image quality?

Use bicubic sampling and avoid over-compressing JPGs to preserve image quality when resizing. Sharpen images after resizing to regain clarity.

  1. What are the best image dimensions for web?

For web, resized images should be 72 dpi with dimensions optimized for layouts. Common sizes are 800-1200 pixels wide for flexible image resizing.

  1. How do I batch resize many images at once?

You can batch process images using Photoshop, GIMP, or command line tools like ImageMagick. Many CMS platforms also have batch resize capabilities.

  1. What are the main benefits of resizing images for web?

Resizing provides faster load times, lower bandwidth usage, improved layout flexibility, and a more consistent viewing experience across devices for web images.

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