Zoom out with Gamma adjusted on imagery causes Exception

What steps will reproduce the problem?

1. Add a Bing Imagery Layer
2. Adjust Gamma for background imagery
3. Adjust zoom in map
4. java.lang.IllegalArgumentException

What is the expected result?

Zoom adjusted in background imagery

What happens instead?

java.lang.IllegalArgumentException

Please provide any additional information below. Attach a screenshot if possible.

Revision: 8732
Repository Root: http://josm.openstreetmap.de/svn
Relative URL: ^/trunk
Last Changed Author: simon04
Last Changed Date: 2015-09-06 21:42:03 +0200 (Sun, 06 Sep 2015)
Build-Date: 2015-09-07 01:32:16
URL: http://josm.openstreetmap.de/svn/trunk
Repository UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last Changed Rev: 8732

Identification: JOSM/1.5 (8732 en_GB) Windows 10 64-Bit
Memory Usage: 556 MB / 1790 MB (121 MB allocated, but free)
Java version: 1.8.0_60, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
Dataset consistency test: No problems found

Plugins:
- commons-imaging (31241)
- ext_tools (31241)
- imagery-xml-bounds (31530)
- rasterfilters (31509)

Last errors/warnings:
- E: java.lang.IllegalArgumentException: Number of channels in the src (4) does not match number of channels in the destination (3)
- E: java.lang.IllegalArgumentException: Number of channels in the src (4) does not match number of channels in the destination (3)
- E: java.lang.IllegalArgumentException: Number of channels in the src (4) does not match number of channels in the destination (3)

java.lang.IllegalArgumentException: Number of channels in the src (4) does not match number of channels in the destination (3)
	at java.awt.image.LookupOp.filter(Unknown Source)
	at java.awt.image.LookupOp.filter(Unknown Source)
	at org.openstreetmap.josm.gui.layer.ImageryLayer$GammaImageProcessor.process(ImageryLayer.java:298)
	at org.openstreetmap.josm.gui.layer.ImageryLayer.applyImageProcessors(ImageryLayer.java:372)
	at org.openstreetmap.josm.gui.layer.AbstractTileSourceLayer.paintTileImages(AbstractTileSourceLayer.java:1030)
	at org.openstreetmap.josm.gui.layer.AbstractTileSourceLayer.paint(AbstractTileSourceLayer.java:1440)
	at org.openstreetmap.josm.gui.MapView.paintLayer(MapView.java:645)
	at org.openstreetmap.josm.gui.MapView.paint(MapView.java:729)
	at javax.swing.JComponent.paintChildren(Unknown Source)
	at javax.swing.JComponent.paint(Unknown Source)
	at javax.swing.JComponent.paintChildren(Unknown Source)
	at javax.swing.JSplitPane.paintChildren(Unknown Source)
	at javax.swing.JComponent.paint(Unknown Source)
	at javax.swing.JComponent.paintChildren(Unknown Source)
	at javax.swing.JComponent.paint(Unknown Source)
	at javax.swing.JComponent.paintToOffscreen(Unknown Source)
	at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
	at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
	at javax.swing.RepaintManager.paint(Unknown Source)
	at javax.swing.JComponent._paintImmediately(Unknown Source)
	at javax.swing.JComponent.paintImmediately(Unknown Source)
	at javax.swing.RepaintManager$4.run(Unknown Source)
	at javax.swing.RepaintManager$4.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
	at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
	at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source)
	at javax.swing.RepaintManager.access$1200(Unknown Source)
	at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source)
	at java.awt.event.InvocationEvent.dispatch(Unknown Source)
	at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
	at java.awt.EventQueue.access$500(Unknown Source)
	at java.awt.EventQueue$3.run(Unknown Source)
	at java.awt.EventQueue$3.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.awt.EventQueue.dispatchEvent(Unknown Source)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
	at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.awt.EventDispatchThread.run(Unknown Source)