dlvr.it can help to control the image or photo that is Automatically posted to Facebook. These images will display on your Facebook page, right next to your content. This Facebook feature contrasts with Twitter, which only allows up to 140 characters of text (any images are hosted on other services and available via a link in the tweet). The addition of an image can enhance your content and engage users with a visual connection to your headlines and text.
The most reliable way to control the images included with Facebook posts is to include OpenGraph tags on your pages. Facebook has officially changed their systems so that dlvr.it is unable to control which thumbnail appears in their systems.
Here's more on OpenGraph:
If you have OpenGraph tags on your pages, you can select the 'auto-detected by Facebook' option above. Facebook will scan the page looking for images -- and include the 'best' image. Typically, Facebook will include the OpenGraph image (og:image).
Facebook Sharing Best Practices
Social Media Pro Tip:
Try dlvr.it's Free Facebook Auto Poster