diff --git a/README.md b/README.md
index bd70fcd..4c5b51e 100644
--- a/README.md
+++ b/README.md
@@ -151,7 +151,9 @@ easyMDE.value('New input for **EasyMDE**');
 - **uploadImage**: If set to `true`, enables the image upload functionality, which can be triggered by drag&drop, copy-paste and through the browse-file window (opened when the user click on the *upload-image* icon). Defaults to `false`.
 - **imageMaxSize**: Maximum image size in bytes, checked before upload (note: never trust client, always check image size at server-side). Defaults to `1024*1024*2` (2Mb).
 - **imageAccept**: A comma-separated list of mime-types used to check image type before upload (note: never trust client, always check file types at server-side). Defaults to `image/png, image/jpeg`.
-- **imageUploadEndpoint**: The endpoint where the images data will be sent, via an asynchronous *POST* request. The server is supposed to save this image, and return a 200-OK HTTP response containing: `{"data": {"filePath": "<imageFilePath>"}}` where *imageFilePath* is the relative path of the image, otherwise, return `{"error": "<errorCode>"}`, where *errorCode* can be `noFileGiven`, `imageTypeNotAllowed`, `imageTooLarge` or `imageImportError` (see *errorMessages* below). No default value.
+- **imageUploadEndpoint**: The endpoint where the images data will be sent, via an asynchronous *POST* request. The server is supposed to save this image, and return a json response.
+     - if the request was successfully processed (HTTP 200-OK): `{"data": {"filePath": "<filePath>"}}` where *filePath* is the relative path of the image;
+     - otherwise: `{"error": "<errorCode>"}`, where *errorCode* can be `noFileGiven` (HTTP 400), `typeNotAllowed` (HTTP 415), `fileTooLarge` (HTTP 413) or `importError` (see *errorMessages* below). No default value.
 - **imageTexts**: Texts displayed to the user (mainly on the status bar) for the import image feature, where `#image_name#`, `#image_size#` and `#image_max_size#` will replaced by their respective values, that can be used for customization or internationalization:
     - **sbInit**: Status message displayed initially if `uploadImage` is set to `true`. Defaults to `Attach files by drag and dropping or pasting from clipboard.`.
     - **sbOnDragEnter**: Status message displayed when the user drags a file to the text area. Defaults to `Drop image to upload it.`.
diff --git a/src/js/easymde.js b/src/js/easymde.js
index c151668..b854152 100644
--- a/src/js/easymde.js
+++ b/src/js/easymde.js
@@ -1431,10 +1431,10 @@ var imageTexts = {
  */
 var errorMessages = {
     noFileGiven: 'You must select a file.',
-    imageTypeNotAllowed: 'This image type is not allowed.',
-    imageTooLarge: 'Image #image_name# is too big (#image_size#).\n' +
+    typeNotAllowed: 'This image type is not allowed.',
+    fileTooLarge: 'Image #image_name# is too big (#image_size#).\n' +
         'Maximum file size is #image_max_size#.',
-    imageImportError: 'Something went wrong when uploading the image #image_name#.',
+    importError: 'Something went wrong when uploading the image #image_name#.',
 };
 
 /**
@@ -1924,7 +1924,7 @@ EasyMDE.prototype.uploadImage = function(file, onSuccess, onError) {
     }
 
     if (file.size > this.options.imageMaxSize) {
-        onError(fillErrorMessage(this.options.errorMessages.imageTooLarge));
+        onError(fillErrorMessage(this.options.errorMessages.fileTooLarge));
     }
 
     var formData = new FormData();
@@ -1946,7 +1946,7 @@ EasyMDE.prototype.uploadImage = function(file, onSuccess, onError) {
             var response = JSON.parse(this.responseText);
         } catch (error) {
             console.log('EasyMDE: The server did not return a valid json.');
-            onError(fillErrorMessage(self.options.errorMessages.imageImportError));
+            onError(fillErrorMessage(self.options.errorMessages.importError));
             return;
         }
         if(this.status === 200 && response && !response.error && response.data && response.data.filePath) {
@@ -1957,7 +1957,7 @@ EasyMDE.prototype.uploadImage = function(file, onSuccess, onError) {
             } else {
                 console.log('EasyMDE: Received an unexpected response after uploading the image.'
                     + this.status + ' (' + this.statusText + ')');
-                onError(fillErrorMessage(self.options.errorMessages.imageImportError));
+                onError(fillErrorMessage(self.options.errorMessages.importError));
             }
         }
     };
@@ -1965,7 +1965,7 @@ EasyMDE.prototype.uploadImage = function(file, onSuccess, onError) {
     request.onerror = function (event) {
         console.log('EasyMDE: An unexpected error occurred when trying to upload the image.'
             + event.target.status + ' (' + event.target.statusText + ')');
-        onError(self.options.errorMessages.imageImportError);
+        onError(self.options.errorMessages.importError);
     };
 };