Surveillance applications with Wireless Sensor Networks can be strengthened by introducing imaging capability: intrusion detection, situation awareness, search&rescue. As images are usually bigger than scalar data, and a single image needs to be split in many small packets, image transmission is a real challenge for these applications, especially when knowing that the wireless medium in WSN has high throughput limitations and high packet loss rates due to numerous wireless channel errors and contention. Our contribution in this paper is on identifying limitations and bottlenecks of sensor board hardware and 802.15.4 radio to determine the performance level that can be expected when transmitting still images on a multi-hop network. In this paper, we will present experimentations with real sensor boards and radio modules. We will highlight the main sources of delays assuming no flow control nor congestion control to determine the best case performance level. The objective here is to present the potentials and the limitations of image-based wireless sensor networks.