Due to J4:
An auto resize plugin does already exist in Joomla 4.
but not perfect because of the quality aspect: See #26511

To enable the plugin by default in the CMS.

I think destructive features shouldn't generally be enabled by default. It's activated in J4 but you have to enter the sizes first.

Please add the file renaming code to the image editing plugin.
I used to write myself a plugin J3 for renaming uploaded photos.
So that test editors and creators of unique content don't have problems with photo names when they suddenly have the same file name.
To prefix the file name with the date and material ID.
So that everything happens automatically.

use Joomla\CMS\Factory as JFactory;
use Joomla\CMS\Plugin\CMSPlugin as JPlugin;
class plgSystemImageRename extends JPlugin {
    public function __construct(&$subject, $config=array()) 

        $image_rename = $this->params->get("image_auto_rename",FALSE);            
        if(empty($image_rename))            return; 

        $this->input = JFactory::getApplication()->input; 
	$files2        = $this->input->files->get('Filedata', array(), 'array');     

        if(empty($files2) && empty($_FILES['Filedata']))            return;
           
        if(is_array($_FILES['Filedata']['name'])){// && isset($file['name'])
            foreach ($_FILES['Filedata']['name'] as $i => &$file)
                $_FILES['Filedata']['name'][$i] = $this->getNewName($_FILES['Filedata']['name'][$i]);
        }
        elseif(is_string($_FILES['Filedata']['name'])){
            $_FILES['Filedata']['name'] = $this->getNewName($_FILES['Filedata']['name']);
        }
            
        if(empty($files2))                return;
            
        if(isset($files2['name'])){
             $files2['name'] = $this->getNewName($files2['name']);
        }
        elseif (isset($files2[0]['name'])) {
            foreach ($files2 as $i => &$file)
                $file['name'] = $this->getNewName($file['name']);
        }
    }
    public function getNewName($str = ''){ 
        $image_date_rename = $this->params->get("image_date_rename",FALSE);
        $image_format_rename = $this->params->get("image_format_rename","Ymd_");
            if($image_date_rename == 2 && $image_format_rename)
                $str = date($image_format_rename).$str;
            elseif($image_date_rename)
                $str = date("Ymd_").$str;
            $str = str_replace(' ', '_', $str);
            $str = str_replace('-', '_', $str);
            $str = JFactory::getLanguage()->transliterate($str);  
            return $str;
    }
}