Magento – Magento 2 stop (or) avoid resize product image at admin end

You can check in details by click, Resize Custom Image in Magento 2

Inside Block file keep below code,

   protected $_filesystem ;
   protected $_imageFactory;
   public function __construct(            
        \Magento\Framework\Filesystem $filesystem,         
        \Magento\Framework\Image\AdapterFactory $imageFactory         
        ) {         
        $this->_filesystem = $filesystem;               
        $this->_imageFactory = $imageFactory;         
        }

    // pass imagename, width and height
    public function resize($image, $width = null, $height = null)
    {
        $absolutePath = $this->_filesystem->getDirectoryRead(\Magento\Framework\App\Filesystem\DirectoryList::MEDIA)->getAbsolutePath('custom_module/posts/').$image;
        if (!file_exists($absolutePath)) return false;
        $imageResized = $this->_filesystem->getDirectoryRead(\Magento\Framework\App\Filesystem\DirectoryList::MEDIA)->getAbsolutePath('resized/'.$width.'/').$image;
        if (!file_exists($imageResized)) { // Only resize image if not already exists.
            //create image factory...
            $imageResize = $this->_imageFactory->create();         
            $imageResize->open($absolutePath);
            $imageResize->constrainOnly(TRUE);         
            $imageResize->keepTransparency(TRUE);         
            $imageResize->keepFrame(FALSE);         
            $imageResize->keepAspectRatio(TRUE);         
            $imageResize->resize($width,$height);  
            //destination folder                
            $destination = $imageResized ;    
            //save image      
            $imageResize->save($destination);         
        } 
        $resizedURL = $this->_storeManager->getStore()->getBaseUrl(\Magento\Framework\UrlInterface::URL_TYPE_MEDIA).'resized/'.$width.'/'.$image;
        return $resizedURL;
  } 

Now Call inside phtml file,

$block->resize('test.jpg',500,400);

In the end I created a new theme to override the following two files where the restriction was added:

• vendor/magento/module-cms/view/adminhtml/templates/browser/content/uploader.phtml
• vendor/magento/module-backend/view/adminhtml/templates/media/uploader.phtml

Within those files I hard coded the new max image sizes:

"maxWidth":3000,
"maxHeight":3000

This is the post I followed to achieve the override: https://magento.stackexchange.com/a/153968/191

Regarding the image file size I have not found a definitive answer as to why the size has more than doubled. This post had some insight however: https://stackoverflow.com/questions/14008524/why-smaller-png-image-takes-up-more-space-than-the-original-after-getting-resize