Change lines 223-237:

    $width  = $this->sourceWidth;
    $height = $this->sourceHeight;
    $x = $y = 0;
    switch (@$this->options['method']) {
      case "shave_all":
        if ($width > $height)
        {
          $x = ceil(($width - $height) / 2 );
          $width = $height;
        }
        elseif ($height > $width)
        {
          $y = ceil(($height - $width) / 2);
          $height = $width;
        }

to:

    $width  = $this->sourceWidth;
    $height = $this->sourceHeight;
    $mWidth = $this->maxWidth;
    $mHeight = $this->maxHeight;
    $x = $y = 0;
    switch (@$this->options['method']) {
      case "shave_all":
        if ($width > $height)
        {
          $x = ceil(($width - ($height*$mWidth)/$mHeight) / 2 );
          $width = $height;
        }
        elseif ($height > $width)
        {
          $y = ceil(($height - $width*($mHeight/$mWidth)) / 2);
          $height = $width;
        }

The plugin's "shave_all" function was not properly cropping and resizing the thumbnails for me. The following needs to be changed in sfImageMagickAdapter.class.php

ImageMagick sfThumbnail Plugin fix under symfony

plugin

PHP