diff --git a/CImage.php b/CImage.php
index 7535a72..5a1f09b 100644
--- a/CImage.php
+++ b/CImage.php
@@ -186,6 +186,7 @@ class CImage
      * Path to command for filter optimize, for example optipng or null.
      */
     private $pngFilter;
+    private $pngFilterCmd;
 
 
 
@@ -193,13 +194,16 @@ class CImage
      * Path to command for deflate optimize, for example pngout or null.
      */
     private $pngDeflate;
+    private $pngDeflateCmd;
 
 
 
     /**
      * Path to command to optimize jpeg images, for example jpegtran or null.
      */
-    private $jpegOptimize;
+     private $jpegOptimize;
+     private $jpegOptimizeCmd;
+
 
 
     /**
@@ -275,6 +279,56 @@ class CImage
     private $fillToFit;
 
 
+
+    /**
+     * To store value for option scale.
+     */
+    private $scale;
+
+
+
+    /**
+     * To store value for option.
+     */
+    private $rotateBefore;
+
+
+
+    /**
+     * To store value for option.
+     */
+    private $rotateAfter;
+
+
+
+    /**
+     * To store value for option.
+     */
+    private $autoRotate;
+
+
+
+    /**
+     * To store value for option.
+     */
+    private $sharpen;
+
+
+
+    /**
+     * To store value for option.
+     */
+    private $emboss;
+
+
+
+    /**
+     * To store value for option.
+     */
+    private $blur;
+
+
+
     /**
      * Used with option area to set which parts of the image to use.
      */
@@ -405,7 +459,7 @@ class CImage
     /**
      * Use cache or not.
      *
-     * @param string $use true or false to use cache.
+     * @param boolean $use true or false to use cache.
      *
      * @return $this
      */
@@ -418,20 +472,20 @@ class CImage
 
 
     /**
-     * Create and save a dummy image.
+     * Create and save a dummy image. Use dimensions as stated in
+     * $this->newWidth, or $width or default to 100 (same for height.
      *
-     * @param boolean $allow   true or false to enable and disable.
-     * @param string  $pattern to use to detect if its a remote file.
+     * @param integer $width  use specified width for image dimension.
+     * @param integer $height use specified width for image dimension.
      *
      * @return $this
      */
-    public function createDummyImage($width = 100, $height = 100)
+    public function createDummyImage($width = null, $height = null)
     {
-        $img = $this->CreateImageKeepTransparency($width, $height);
+        $this->newWidth  = $this->newWidth  ?: $width  ?: 100;
+        $this->newHeight = $this->newHeight ?: $height ?: 100;
 
-        $this->generateFilename($cachePath);
-
-        $this->save();
+        $this->image = $this->CreateImageKeepTransparency($this->newWidth, $this->newHeight);
 
         return $this;
     }
@@ -626,18 +680,23 @@ class CImage
      * Set target file.
      *
      * @param string $src of target image.
-     * @param string $dir as base directory where images are stored.
+     * @param string $dir as optional base directory where images are stored.
+     *                    Uses $this->saveFolder if null.
      *
      * @return $this
      */
     public function setTarget($src = null, $dir = null)
     {
-        if (!(isset($src) && isset($dir))) {
+        if (!isset($src)) {
+            $this->cacheFileName = null;
             return $this;
         }
 
-        $this->saveFolder     = $dir;
-        $this->cacheFileName  = $dir . '/' . $src;
+        if (isset($dir)) {
+            $this->saveFolder = rtrim($dir, '/');
+        }
+
+        $this->cacheFileName  = $this->saveFolder . '/' . $src;
 
         // Sanitize filename
         $this->cacheFileName = preg_replace('/^a-zA-Z0-9\.-_/', '', $this->cacheFileName);
@@ -648,6 +707,18 @@ class CImage
 
 
 
+    /**
+     * Get filename of target file.
+     *
+     * @return Boolean|String as filename of target or false if not set.
+     */
+    public function getTarget()
+    {
+        return $this->cacheFileName;
+    }
+
+
+
     /**
      * Set options to use when processing image.
      *
@@ -1188,13 +1259,15 @@ class CImage
     /**
      * Generate filename to save file in cache.
      *
-     * @param string $base as basepath for storing file.
+     * @param string  $base      as optional basepath for storing file.
+     * @param boolean $useSubdir use or skip the subdir part when creating the
+     *                           filename.
      *
      * @return $this
      */
-    public function generateFilename($base)
+    public function generateFilename($base = null, $useSubdir = true)
     {
-        $parts        = pathinfo($this->pathToImage);
+        $filename     = basename($this->pathToImage);
         $cropToFit    = $this->cropToFit    ? '_cf'                      : null;
         $fillToFit    = $this->fillToFit    ? '_ff'                      : null;
         $crop_x       = $this->crop_x       ? "_x{$this->crop_x}"        : null;
@@ -1236,16 +1309,6 @@ class CImage
 
         $autoRotate = $this->autoRotate ? 'ar' : null;
 
-        $this->extension = isset($this->extension)
-            ? $this->extension
-            : (isset($parts['extension'])
-                ? $parts['extension']
-                : null);
-        
-        $extension = empty($this->extension)
-            ? null
-            : "." . $this->extension;
-
         $optimize  = $this->jpegOptimize ? 'o' : null;
         $optimize .= $this->pngFilter    ? 'f' : null;
         $optimize .= $this->pngDeflate   ? 'd' : null;
@@ -1260,16 +1323,20 @@ class CImage
             $upscale = '_nu';
         }
 
-        $subdir = str_replace('/', '-', dirname($this->imageSrc));
-        $subdir = ($subdir == '.') ? '_.' : $subdir;
-        $file = $subdir . '_' . $parts['filename'] . '_' . $width . '_'
+        $subdir = null;
+        if ($useSubdir === true) {
+            $subdir = str_replace('/', '-', dirname($this->imageSrc));
+            $subdir = ($subdir == '.') ? '_.' : $subdir;
+            $subdir .= '_';
+        }
+        
+        $file = $subdir . $filename . '_' . $width . '_'
             . $height . $offset . $crop . $cropToFit . $fillToFit
             . $crop_x . $crop_y . $upscale
             . $quality . $filters . $sharpen . $emboss . $blur . $palette
             . $optimize . $compress
             . $scale . $rotateBefore . $rotateAfter . $autoRotate . $bgColor
-            . $convolve
-            . $extension;
+            . $convolve;
 
         return $this->setTarget($file, $base);
     }
@@ -2037,7 +2104,10 @@ class CImage
         imagealphablending($img, false);
         imagesavealpha($img, true);
 
-        $index = imagecolortransparent($this->image);
+        $index = $this->image
+            ? imagecolortransparent($this->image)
+            : -1;
+            
         if ($index != -1) {
 
             imagealphablending($img, true);
@@ -2110,17 +2180,23 @@ class CImage
     /**
      * Save image.
      *
-     * @param string $src  as target filename.
-     * @param string $base as base directory where to store images.
+     * @param string  $src       as target filename.
+     * @param string  $base      as base directory where to store images.
+     * @param boolean $overwrite or not, default to always overwrite file.
      *
      * @return $this or false if no folder is set.
      */
-    public function save($src = null, $base = null)
+    public function save($src = null, $base = null, $overwrite = true)
     {
         if (isset($src)) {
             $this->setTarget($src, $base);
         }
 
+        if ($overwrite === false && is_file($this->cacheFileName)) {
+            $this->Log("Not overwriting file since its already exists and \$overwrite if false.");
+            return;
+        }
+
         is_writable($this->saveFolder)
             or $this->raiseError('Target directory is not writable.');
 
diff --git a/REVISION.md b/REVISION.md
index bb6765a..2d988ab 100644
--- a/REVISION.md
+++ b/REVISION.md
@@ -8,7 +8,9 @@ Revision history
 v0.7.5x (latest)
 -------------------------------------
 
-* Add option for png compression to generade filename, fix #103.
+* Add png compression to generated cache filename, fix #103.
+* Removed file prefix from storing images in cache, breaking filenamestructure for cache images.
+* Minor code cleaning in `CImage.php`.
 
 
 v0.7.4 (2015-09-15)
diff --git a/cache/dummy/README.md b/cache/dummy/README.md
new file mode 100644
index 0000000..347bc3a
--- /dev/null
+++ b/cache/dummy/README.md
@@ -0,0 +1 @@
+This directory must be writable by the webserveri to enable the dummy feature.
diff --git a/test/CImageDummyTest.php b/test/CImageDummyTest.php
new file mode 100644
index 0000000..6d831ee
--- /dev/null
+++ b/test/CImageDummyTest.php
@@ -0,0 +1,49 @@
+<?php
+/**
+ * A testclass
+ *
+ */
+class CImageDummyTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * Test
+     *
+     * @return void
+     */
+    public function testCreate1()
+    {
+        $img = new CImage();
+
+        $img->setSaveFolder(CACHE_PATH . "/dummy");
+        $img->setSource('dummy', CACHE_PATH . "/dummy");
+        $img->createDummyImage();
+        $img->generateFilename(null, false);
+        $img->save(null, null, false);
+
+        $filename = $img->getTarget();
+
+        $this->assertEquals(basename($filename), "dummy_100_100", "Filename not as expected on dummy image.");
+    }
+
+
+
+    /**
+     * Test
+     *
+     * @return void
+     */
+    public function testCreate2()
+    {
+        $img = new CImage();
+
+        $img->setSaveFolder(CACHE_PATH . "/dummy");
+        $img->setSource('dummy', CACHE_PATH . "/dummy");
+        $img->createDummyImage(200, 400);
+        $img->generateFilename(null, false);
+        $img->save(null, null, false);
+
+        $filename = $img->getTarget();
+
+        $this->assertEquals(basename($filename), "dummy_200_400", "Filename not as expected on dummy image.");
+    }
+}
diff --git a/test/config.php b/test/config.php
index e53e4b1..4933b03 100644
--- a/test/config.php
+++ b/test/config.php
@@ -4,3 +4,6 @@
  *
  */
 require __DIR__ . "/../autoload.php";
+
+define('IMAGE_PATH', __DIR__ . '/../webroot/img/');
+define('CACHE_PATH', __DIR__ . '/../cache/');
diff --git a/webroot/img.php b/webroot/img.php
index 2e962cf..3c4e222 100644
--- a/webroot/img.php
+++ b/webroot/img.php
@@ -373,10 +373,20 @@ $imagePath           = getConfig('image_path', __DIR__ . '/img/');
 $imagePathConstraint = getConfig('image_path_constraint', true);
 $validFilename       = getConfig('valid_filename', '#^[a-z0-9A-Z-/_ \.:]+$#');
 
+// Dumm image feature
+$dummyEnabled  = getConfig('dummy_enabled', true);
+$dummyFilename = getConfig('dummy_filename', 'dummy');
+$dummyImage = false;
+
 preg_match($validFilename, $srcImage)
     or errorPage('Filename contains invalid characters.');
 
-if ($allowRemote && $img->isRemoteSource($srcImage)) {
+if ($dummyEnabled && $srcImage === $dummyFilename) {
+
+    // Prepare to create a dummy image and use it as the source image.
+    $dummyImage = true;
+
+} elseif ($allowRemote && $img->isRemoteSource($srcImage)) {
 
     // If source is a remote file, ignore local file checks.
 
@@ -933,9 +943,43 @@ if ($verboseFile) {
 
 
 
- /**
-  * Load, process and output the image
-  */
+/**
+ * Set basic options for image processing.
+ */
+
+
+/**
+ * Prepare a dummy image and use it as source image.
+ */
+if ($dummyImage === true) {
+    
+    $dummyDir = getConfig('dummy_dir', $cachePath. "/" . $dummyFilename);
+
+    is_writable($dummyDir)
+        or verbose("dummy dir not writable = $dummyDir");
+
+    $img->setSaveFolder($dummyDir)
+        ->setSource($dummyFilename, $dummyDir)
+        ->setOptions(
+            array(
+                'bgColor'    => $bgColor,
+            )
+        )
+        ->createDummyImage()
+        ->generateFilename(null, false)
+        ->save(null, null, false);
+
+    $srcImage = $img->getTarget();
+    $imagePath = null;
+    
+    verbose("src (updated) = $srcImage");
+}
+
+
+
+/**
+ * Load, process and output the image
+ */
 $img->log("Incoming arguments: " . print_r(verbose(), 1))
     ->setSaveFolder($cachePath)
     ->useCache($useCache)
diff --git a/webroot/img_config.php b/webroot/img_config.php
index 64223a2..88da39a 100644
--- a/webroot/img_config.php
+++ b/webroot/img_config.php
@@ -109,6 +109,28 @@ return array(
 
 
 
+     /**
+      * The name representing a dummy image which is automatically created
+      * and stored at the defined path. The dummy image can then be used
+      * inplace of an original image as a placeholder.
+      * The dummy_dir must be writable and it defaults to a subdir of the
+      * cache directory.
+      * Write protect the dummy_dir to prevent creation of new dummy images,
+      * but continue to use the existing ones.
+      *
+      * Default value:
+      *  dummy_enabled:  true as default, disable dummy feature by setting
+      *                  to false.
+      *  dummy_filename: 'dummy' use this as ?src=dummy to create a dummy image.
+      *  dummy_dir:      Defaults to subdirectory of 'cache_path',
+      *                  named the same as 'dummy_filename'
+      */
+      //'dummy_enabled' => true,
+      //'dummy_filename' => 'dummy',
+      //'dummy_dir' => 'some writable directory',
+
+
+
      /**
      * Check that the imagefile is a file below 'image_path' using realpath().
      * Security constraint to avoid reaching images outside image_path.