Bug 61950 [Markers] Images being created twice potentially
org.eclipse.ui.views.internal is using a static called ImageFactory which has it's own ImageRegistry. It should use JFaceResources.getImageRegistry to be sure that images are not being created twice (Image creation can be very expensive). I am not sure that this is a problem currently with performance but it could add to start up time.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/markers/internal/FieldSeverity.java
if (obj == null || !(obj instanceof ProblemMarker)) {
            return null;
        }
        int severity = ((ProblemMarker) obj).getSeverity();
        if (severity == IMarker.SEVERITY_ERROR) {
            return ImageFactory.getImage(IMAGE_ERROR_PATH);
        }
        if (severity == IMarker.SEVERITY_WARNING) {
            return ImageFactory.getImage(IMAGE_WARNING_PATH);
        }
        if (severity == IMarker.SEVERITY_INFO) {
            return ImageFactory.getImage(IMAGE_INFO_PATH);
        }
        return null;
    }
    /*
     *  (non-Javadoc)
     * @see org.eclipse.ui.views.markers.internal.IField#compare(java.lang.Object, java.lang.Object)
     */
    public int compare(Object obj1, Object obj2) {
        if (obj1 == null || obj2 == null || !(obj1 instanceof ProblemMarker)
                || !(obj2 instanceof ProblemMarker)) {
            return 0;
        }
        int severity1 = ((ProblemMarker) obj1).getSeverity();
        int severity2 = ((ProblemMarker) obj2).getSeverity();
        return severity1 - severity2;
    }
}