feat: add onImgLoad to img and background

Author: amrelbialy

README.md

@@ -328,7 +328,14 @@ relative to baseUrl in your config.
 
 The plugin uses a special algorithm to detect the width of image container and set the image size accordingly.
 This is the recommended way of using the Cloudimage Responsive plugin.
-
+### onImgLoad
+###### Type: **function** | Default: **undefined**
+A function to be executed after the image is loaded
+```jsx
+<Img
+  src="dino-reichmuth-1.jpg"
+  onImgLoad={(params)=>{console.log(params);}}/>
+```
 ### width
 
 ###### Type: **String** (e.g. 300px, 20vw) | Default: **undefined**