See https://sourceforge.net/p/openil/patches/50/

--- src-IL/src/il_targa.c	(revision 1678)
+++ src-IL/src/il_targa.c	(working copy)
@@ -219,6 +219,9 @@
 			ilSetError(IL_ILLEGAL_FILE_VALUE);
 			return IL_FALSE;
 	}
+
+	if (bTarga==IL_FALSE)
+		return IL_FALSE;
 	
 	// @JASON Extra Code to manipulate the image depending on
 	// the Image Descriptor's origin bits.