Image rendition is a new capability in SharePoint 2013 helps you to optimize images in your SharePoint site through having the same image but in different sizes. This will enhance the user experience through browsing the SharePoint site from different devices, like laptop or mobile.
How does it work?
Simply when you upload an image, SharePoint will give you the ability to resize the image.
1- Create a publishing site collection.
2- Click on site contents
3- Click on SETTINGS
4- Under Look and Feel Section, click on Image Rendition
5- You will notice an error on the top of the page. This is because the BLOB Cache is not configured
6- Enable BLOB Cache:
a. Go to web.config
b. Search for BlobCache Section
c. Change the value of the attribute enabled to “true”
d. Save and close web.config
7- Refresh Image Rendition.
8- By default, there will be 4 predefined rendition configured on your SharePoint site.
9- Create a new rendition, by adding new item link
10- Enter the Name, width and height, and then click Save.
11- Each rendition type has a unique ID. This ID will be used as a URL parameter to render the required image size.
12- Upload an image to Image Library
13- Hover the cursor on the uploaded image and then click on …, then on Edit Rendition
14- Click on “Click to Change” for the display template 100*100
15- Move the selected area for the needed space and click save
16- Create a new Article Page
17- Edit the page and add an image to on the left
18- Select the image on the left
19- On the top bar, click on Image, Click on Pick Rendition.
20- Choose the required setting to show the image.