diff --git a/jme3-core/src/main/java/com/jme3/renderer/Renderer.java b/jme3-core/src/main/java/com/jme3/renderer/Renderer.java
index e3dd20c92..608ac9d15 100644
--- a/jme3-core/src/main/java/com/jme3/renderer/Renderer.java
+++ b/jme3-core/src/main/java/com/jme3/renderer/Renderer.java
@@ -115,6 +115,9 @@ public interface Renderer {
 
     /**
      * Called when a new frame has been rendered.
+     * 
+     * Currently, this will simply delete any OpenGL objects from the GPU
+     * which have been garbage collected by the GC.
      */
     public void postFrame();
 
@@ -161,6 +164,7 @@ public interface Renderer {
      * the attached shader sources.
      * 
      * @param shader Shader to delete.
+     * @see #deleteShaderSource(com.jme3.shader.Shader.ShaderSource) 
      */
     public void deleteShader(Shader shader);
 
@@ -179,6 +183,11 @@ public interface Renderer {
 
     /**
      * Sets the framebuffer that will be drawn to.
+     * 
+     * If the framebuffer has not been initialized yet, it will be created
+     * and its render surfaces and attached textures will be allocated.
+     * 
+     * @param fb The framebuffer to set
      */
     public void setFrameBuffer(FrameBuffer fb);
     
@@ -186,7 +195,7 @@ public interface Renderer {
      * Set the framebuffer that will be set instead of the main framebuffer
      * when a call to setFrameBuffer(null) is made.
      * 
-     * @param fb 
+     * @param fb The framebuffer to override the main framebuffer.
      */
     public void setMainFrameBufferOverride(FrameBuffer fb);
 
diff --git a/jme3-core/src/main/java/com/jme3/system/JmeSystem.java b/jme3-core/src/main/java/com/jme3/system/JmeSystem.java
index 14c4acb7d..637b24304 100644
--- a/jme3-core/src/main/java/com/jme3/system/JmeSystem.java
+++ b/jme3-core/src/main/java/com/jme3/system/JmeSystem.java
@@ -117,6 +117,20 @@ public class JmeSystem {
         return systemDelegate.getSoftTextDialogInput();
     }
 
+    /**
+     * Compresses a raw image into a stream.
+     * 
+     * The encoding is performed via system libraries. On desktop, the encoding
+     * is performed via ImageIO, whereas on Android, is is done via the 
+     * Bitmap class.
+     * 
+     * @param outStream The stream where to write the image data.
+     * @param format The format to use, either "png" or "jpg".
+     * @param imageData The image data in {@link Image.Format#RGBA8} format.
+     * @param width The width of the image.
+     * @param height The height of the image.
+     * @throws IOException If outStream throws an exception while writing.
+     */
     public static void writeImageFile(OutputStream outStream, String format, ByteBuffer imageData, int width, int height) throws IOException {
         checkDelegate();
         systemDelegate.writeImageFile(outStream, format, imageData, width, height);