diff --git a/src/stojg/crop/Crop.php b/src/stojg/crop/Crop.php
index 380322f..9379447 100644
--- a/src/stojg/crop/Crop.php
+++ b/src/stojg/crop/Crop.php
@@ -145,7 +145,8 @@ protected function getEntropy($histogram, $area)
     {
         $value = 0.0;
 
-        for ($idx = 0; $idx < count($histogram); $idx++) {
+        $colors = count($histogram);
+        for ($idx = 0; $idx < $colors; $idx++) {
             // calculates the percentage of pixels having this color value
             $p = $histogram[$idx]->getColorCount() / $area;
             // A common way of representing entropy in scalar
diff --git a/src/stojg/crop/CropBalanced.php b/src/stojg/crop/CropBalanced.php
index d3f2be8..d0b956d 100644
--- a/src/stojg/crop/CropBalanced.php
+++ b/src/stojg/crop/CropBalanced.php
@@ -102,7 +102,8 @@ function ($result, $array) {
         $centerY = 0;
 
         // Calulate the mean weighted center x and y
-        for ($idx=0; $idx < count($points); $idx++) {
+        $totalPoints = count($points);
+        for ($idx=0; $idx < $totalPoints; $idx++) {
             $centerX += $points[$idx]['x'] * ($points[$idx]['sum'] / $totalWeight);
             $centerY += $points[$idx]['y'] * ($points[$idx]['sum'] / $totalWeight);
         }
@@ -136,8 +137,9 @@ protected function getHighestEnergyPoint(\Imagick $image)
     {
         $size = $image->getImageGeometry();
         // It's more performant doing random pixel uplook via GD
-        $image->writeimage('/tmp/image');
-        $im = imagecreatefromjpeg('/tmp/image');
+        $tmpFile = sys_get_temp_dir() . DIRECTORY_SEPARATOR . 'image' . rand();
+        $image->writeimage($tmpFile);
+        $im = imagecreatefromjpeg($tmpFile);
         $xcenter = 0;
         $ycenter = 0;
         $sum = 0;
diff --git a/src/stojg/crop/CropEntropy.php b/src/stojg/crop/CropEntropy.php
index 5e6d94d..4d24e70 100644
--- a/src/stojg/crop/CropEntropy.php
+++ b/src/stojg/crop/CropEntropy.php
@@ -253,7 +253,8 @@ protected function colorEntropy(\Imagick $image)
         $newHistogram = array();
 
         // Translates a color histogram into a bw histogram
-        for ($idx = 0; $idx < count($histogram); $idx++) {
+        $colors = count($histogram);
+        for ($idx = 0; $idx < $colors; $idx++) {
             $colors = $histogram[$idx]->getColor();
             $grey = $this->rgb2bw($colors['r'], $colors['g'], $colors['b']);
             if (!isset($newHistogram[$grey])) {