修正方法名错误

index.js

@@ -23,7 +23,7 @@ var dll = ffi.Library(dllPath, {
     designerReport: ['void', ['string', 'string']],
     reportShowPreview: ['void', ['string', 'string']],
     reportPrinter: ['void', ['string', 'string', 'bool']],
-    ReportToImage: ['string', ['string', 'string']],
+    reportToImage: ['string', ['string', 'string']],
     waitSaveOrClose: ['void', ['pointer']]
 });
 var ReportApi = /** @class */ (function () {