diff --git a/engine/common/imagelib/img_quant.c b/engine/common/imagelib/img_quant.c
index eb5e2e50..e450e14f 100644
--- a/engine/common/imagelib/img_quant.c
+++ b/engine/common/imagelib/img_quant.c
@@ -408,7 +408,7 @@ void learn( void )
 		if( rad ) alterneigh( rad, j, r, g, b );   // alter neighbours
 
 		p += step;
-		if( p >= lim ) p -= lengthcount;
+		while( p >= lim ) p -= lengthcount;
 
 		i++;