--- a/mobile/android/chrome/content/browser.js
+++ b/mobile/android/chrome/content/browser.js
@@ -854,17 +854,17 @@ var BrowserApp = {
         UITelemetry.addEvent("action.1", "contextmenu", null, "web_copy_image");
 
         let url = aTarget.src;
         NativeWindow.contextmenus._copyStringToDefaultClipboard(url);
       });
 
     NativeWindow.contextmenus.add({
       label: stringGetter("contextmenu.shareImage"),
-      selector: NativeWindow.contextmenus._disableRestricted("SHARE", NativeWindow.contextmenus.imageSaveableContext),
+      selector: NativeWindow.contextmenus._disableRestricted("SHARE", NativeWindow.contextmenus.imageShareableContext),
       order: NativeWindow.contextmenus.DEFAULT_HTML5_ORDER - 1, // Show above HTML5 menu items
       showAsActions: function(aTarget) {
         let doc = aTarget.ownerDocument;
         let imageCache = Cc["@mozilla.org/image/tools;1"].getService(Ci.imgITools)
                                                          .getImgCacheForDocument(doc);
         let props = imageCache.findEntryProperties(aTarget.currentURI, doc);
         let src = aTarget.src;
         return {
@@ -2434,16 +2434,40 @@ var NativeWindow = {
           // The image must be loaded to allow saving
           let request = aElement.getRequest(Ci.nsIImageLoadingContent.CURRENT_REQUEST);
           return (request && (request.imageStatus & request.STATUS_SIZE_AVAILABLE));
         }
         return false;
       }
     },
 
+    imageShareableContext: {
+      matches: function imageShareableContextMatches(aElement) {
+        let imgSrc = '';
+        if (aElement instanceof Ci.nsIDOMHTMLImageElement) {
+          imgSrc = aElement.src;
+        } else if (aElement instanceof Ci.nsIImageLoadingContent &&
+            aElement.currentURI &&
+            aElement.currentURI.spec) {
+          imgSrc = aElement.currentURI.spec;
+        }
+
+        // In order to share an image, we need to pass the image src over IPC via an Intent (in
+        // `ApplicationPackageManager.queryIntentActivities`). However, the transaction has a 1MB limit
+        // (shared by all transactions in progress) - otherwise we crash! (bug 1243305)
+        //   https://developer.android.com/reference/android/os/TransactionTooLargeException.html
+        //
+        // The transaction limit is 1MB and we arbitrarily choose to cap this transaction at 1/4 of that = 250,000 bytes.
+        // In Java, a UTF-8 character is 1-4 bytes so, 250,000 bytes / 4 bytes/char = 62,500 char
+        let MAX_IMG_SRC_LEN = 62500;
+        let isTooLong = imgSrc.length >= MAX_IMG_SRC_LEN;
+        return !isTooLong && this.NativeWindow.contextmenus.imageSaveableContext.matches(aElement);
+      }.bind(this)
+    },
+
     mediaSaveableContext: {
       matches: function mediaSaveableContextMatches(aElement) {
         return (aElement instanceof HTMLVideoElement ||
                aElement instanceof HTMLAudioElement);
       }
     },
 
     imageBlockingPolicyContext: {