SharePoint 2013 has a new feature called Image Renditions that allows us to optimize images for different devices. Image Rendition allows us to have bigger images stored within SharePoint 2013 site and have different sized variants of the images to be used.
Below are the steps for setting up Image Renditions in SharePoint 2013
1. From the Site Settings page click Image Renditions option under Look and Feel section
2. Default set of 4 Image Renditions with different width and height will be available. You can add a new Image Rendition by specifying a name, width and height.
3. After definining Image Renditions you can edit the renditions for images by navigating to the Image Library and choosing Edit Rendition option from the menu.
4. Edit rendition page displays the image in different renditions and also allows to edit specific rendition.
5. Once you have configured Image Rendition you can use the image in any page in SharePoint site. After inserting the image in to a page you can select Image Rendition you want from the Pick Rendition ribbon
1. Image Rendition depends upon blob cache and it has to be enabled for the web application.
2. Image Rendition is available only for Publishing Portals or when the Publishing Feature is enabled.