core-bundle/src/Resources/contao/library/Contao/Image.php
public static function resize($image, $width, $height, $mode='')
	{
		@trigger_error('Using Image::resize() has been deprecated and will no longer work in Contao 5.0. Use the contao.image.image_factory service instead.', E_USER_DEPRECATED);

		return static::get($image, $width, $height, $mode, $image, true) ? true : false;
	}
public static function resize($image, $width, $height, $mode='')
	{
		@trigger_error('Using Image::resize() has been deprecated and will no longer work in Contao 5.0. Use the contao.image.image_factory service instead.', E_USER_DEPRECATED);

		return static::get($image, $width, $height, $mode, $image, true) ? true : false;
	}
Resize or crop an image and replace the original with the resized version

@param string  $image  The image path
@param integer $width  The target width
@param integer $height The target height
@param string  $mode   The resize mode

@return boolean True if the image could be resized successfully

@deprecated Deprecated since Contao 4.3, to be removed in Contao 5.0.
Use the contao.image.image_factory service instead.