update readme with imagePathAbsolute option info

README.md

@@ -168,9 +168,10 @@ easyMDE.value('New input for **EasyMDE**');
 - **imageUploadFunction**: A custom function for handling the image upload. Using this function will render the options `imageMaxSize`, `imageAccept`, `imageUploadEndpoint` and `imageCSRFToken` ineffective.
     - The function gets a file and onSuccess and onError callback functions as parameters. `onSuccess(imageUrl: string)` and `onError(errorMessage: string)`
 - **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;
+     - if the request was successfully processed (HTTP 200-OK): `{"data": {"filePath": "<filePath>"}}` where *filePath* is the path of the image (absolute if `imagePathAbsolute` is set to true, relative if otherwise);
      - otherwise: `{"error": "<errorCode>"}`, where *errorCode* can be `noFileGiven` (HTTP 400), `typeNotAllowed` (HTTP 415), `fileTooLarge` (HTTP 413) or `importError` (see *errorMessages* below). If *errorCode* is not one of the *errorMessages*, it is alerted unchanged to the user. This allows for server side error messages.
      No default value.
+- **imagePathAbsolute**: If set to `true`, will treat `imageUrl` from `imageUploadFunction` and *filePath* returned from `imageUploadEndpoint` as an absolute rather than relative path, i.e. not prepend `window.location.origin` to it.
 - **imageCSRFToken**: CSRF token to include with AJAX call to upload image. For instance used with Django backend.
 - **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.`.