Replaced image by a version containing all 4 e-Series robots

Author: Felix Exner

README.md

@@ -3,7 +3,7 @@
 # Universal_Robots_ROS_Driver
 Universal Robots have become a dominant supplier of lightweight, robotic manipulators for industry, as well as for scientific research and education. The Robot Operating System (ROS) has developed from a community-centered movement to a mature framework and quasi standard, providing a rich set of powerful tools for robot engineers and researchers, working in many different domains.
 
-<center><img src="ur_robot_driver/doc/initial_setup_images/e-Series.png" alt="Universal Robot e-Series family" style="width: 45%;"/></center>
+<center><img src="ur_robot_driver/doc/initial_setup_images/e-Series.jpg" alt="Universal Robot e-Series family" style="width: 80%;"/></center>
 
 With the release of UR’s new e-Series, the demand for a ROS driver that supports the new manipulators and the newest ROS releases and paradigms like ROS-control has increased further. The goal of this driver is to provide a stable and sustainable interface between UR robots and ROS that strongly benefit all parties.