Activate the following two features:
1.Go to Site Settings -> Site Collection Administrator -> Site Collection Feature->From this activate SharePoint Server Publishing Infrastructure feature.
2.Go to Site Settings -> Site Actions -> Manage Site Features->From that activate SharePoint Server Publishing feature.
1.On the Site Settings page, in the Look and Feel section, click on Image Renditions link
2.On the Image Renditions page, choose Add new item
3.On the New Image Rendition page, in the Name box, enter a name for the rendition
4.In the Width and Height text boxes, enter the width and height, in pixels, of the rendition, and then choose Save.
5.Go to home page and Edit the page.
6.Insert tab, open the Picture group and select From SharePoint
7.Choose your file from picture library.
8.select image and click Image tab
9.Click on Pick Rendition in the Ribbon and choose <Your Rendition>.