To add pictures to your business page, go to your business dashboard and click on business profile, the business dashboard lets you edit many things including adding pictures to your business page.

Click on Maintain Profile, then gallery and add the pictures. You can also add a caption and a description. Images are limited to less than 5mb, the page has an option to help you compress images larger than 5mb. .gif, .jpg, .png, .jpeg are the formats supported.