Update app.js

@@ -82,9 +82,20 @@ async function handleEvent(event) {
   }
   else if (event.type == 'message'&& event.message.type == 'image') {
     return new Promise(async(resolve,reject)=>{  
-      fs.writeFileSync('./photo/image.png',event.message.image)
+
+      client.getMessageContent(event.message.id)
+      .then((stream) => {
+        stream.on('data', (chunk) => {
+          const fs = require('fs');
+          const file = fs.createWriteStream('./photo/image.jpeg');
+          for(let i=0; i<= 1e6; i++) {
+          file.write(chunk);
+          }
+          file.end();
+        });
+      });
       var cheerio = require('cheerio');
-      var file=fs.readFileSync('./photo/image.png');
+      
       var uriBase = 'https://koreacentral.api.cognitive.microsoft.com/vision/v2.1/ocr';
        var options = {
         uri: uriBase,
@@ -94,10 +105,10 @@ async function handleEvent(event) {
           language: 'en'
         },
         headers: {
-          'Content-Type': 'application/octet-stream',
+          'Content-Type': 'application/json',
           'Ocp-Apim-Subscription-Key': '979dc5d63344438fa4701c62feebb7dc'
         },
-        body: file
+        body: fs.readFileSync('./photo/image.jpeg')
       };
       
       request.post(options, function (error, response, body) {