Index: trunk/src/org/openstreetmap/josm/tools/ImageProvider.java
===================================================================
--- trunk/src/org/openstreetmap/josm/tools/ImageProvider.java	(revision 7494)
+++ trunk/src/org/openstreetmap/josm/tools/ImageProvider.java	(revision 7495)
@@ -680,5 +680,11 @@
             BufferedImage img = null;
             try {
-                img = read(path, false, false);
+                // See #10479: for PNG files, always enforce transparency to be sure tNRS chunk is used even not in paletted mode
+                // This can be removed if someday Oracle fixes https://bugs.openjdk.java.net/browse/JDK-6788458
+                // hg.openjdk.java.net/jdk7u/jdk7u/jdk/file/828c4fedd29f/src/share/classes/com/sun/imageio/plugins/png/PNGImageReader.java#l656
+                img = read(path, false, true);
+                if (Main.isDebugEnabled() && isTransparencyForced(img)) {
+                    Main.debug("Transparency has been forced for image "+path.toExternalForm());
+                }
             } catch (IOException e) {
                 Main.warn(e);
@@ -1240,6 +1246,6 @@
                     bi = new BufferedImage(bi.getColorModel(), bi.getRaster(), bi.isAlphaPremultiplied(), properties);
                     if (enforceTransparency) {
-                        if (Main.isDebugEnabled()) {
-                            Main.debug("Enforcing image transparency of "+stream+" for "+color);
+                        if (Main.isTraceEnabled()) {
+                            Main.trace("Enforcing image transparency of "+stream+" for "+color);
                         }
                         bi = makeImageTransparent(bi, color);
@@ -1320,5 +1326,5 @@
     public static BufferedImage makeImageTransparent(BufferedImage bi, Color color) {
         // the color we are looking for. Alpha bits are set to opaque
-        final int markerRGB = color.getRGB() | 0xFFFFFFFF;
+        final int markerRGB = color.getRGB() | 0xFF000000;
         ImageFilter filter = new RGBImageFilter() {
             @Override