diff --git a/lib/tools/redownload/redownload.js b/lib/tools/redownload/redownload.js
index e7d8f26..c567729 100644
--- a/lib/tools/redownload/redownload.js
+++ b/lib/tools/redownload/redownload.js
@@ -421,20 +421,46 @@ var Redownload = function() {
 
                 var image = {
                     url: req.url,
-                    originalWeigth: req.weightCheck.bodySize
+                    originalWeigth: req.weightCheck.bodySize,
                 };
 
+                switch (req.contentType) {
+                    case 'image/jpeg':
+                        image.originalFormat = 'JPEG';
+                        break;
+                    case 'image/png':
+                        image.originalFormat = 'PNG';
+                        break;
+                    case 'image/gif':
+                        image.originalFormat = 'GIF';
+                        break;
+                    case 'image/webp':
+                        image.originalFormat = 'WebP';
+                        break;
+                    case 'image/avif':
+                        image.originalFormat = 'AVIF';
+                        break;
+                }
+
                 if (req.weightCheck.webpSize) {
                     image.webpSize = req.weightCheck.webpSize;
+                    image.webpGain = req.weightCheck.bodySize - req.weightCheck.webpSize;
+                    
+                    image.bestFormat = 'WebP';
+                    image.maxGain = image.webpGain;
                 }
+
                 if (req.weightCheck.avifSize) {
                     image.avifSize = req.weightCheck.avifSize;
+                    image.avifGain = req.weightCheck.bodySize - req.weightCheck.avifSize;
+
+                    if (!req.weightCheck.webpSize || req.weightCheck.webpSize > req.weightCheck.avifSize) {
+                        image.bestFormat = 'AVIF';
+                        image.maxGain = image.avifGain;
+                    }
                 }
 
-                var smallest = Math.min(image.webpSize || Infinity, image.avifSize || Infinity);
-                image.gain = req.weightCheck.bodySize - smallest;
-
-                results.totalGain += image.gain;
+                results.totalGain += image.maxGain;
                 results.images.push(image);
             }
         });
@@ -863,9 +889,9 @@ var Redownload = function() {
 
         debug('Downloading %s', entry.url);
 
-        // Always add compression and webp headers before sending, in case the server listens to them
+        // Always add compression and webp/avif headers before sending, in case the server listens to them
         var reqHeaders = [];
-        reqHeaders['Accept'] = '*/*,image/webp';
+        reqHeaders['Accept'] = '*/*,image/webp,image/avif';
         reqHeaders['Accept-Encoding'] = 'gzip, deflate, br';
         reqHeaders['Connection'] = 'keep-alive';
         reqHeaders['User-Agent'] = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.182 Safari/537.36';