Digital Camera
A wireless camera is a useful tool for a wide variety of applications, most of them not involving very high resolution due to bandwidth constraints. They will typically only transmit images to another device and do not store them on their own which limits the resolution. For wildlife photography the camera has built in memory to take higher quality pictures, often motion activated or remotely triggered.
A wireless camera is very useful for surveillance of large properties or valuable areas such as store fronts. They can be positioned anywhere because they do not need any wires routed to them. The only limitation is the distance from the receiver which acts as both a viewer as well as a storage device. A simplified version is used to monitor babies rooms while they are napping.
Many web cams are digital cameras to eliminate cord clutter as well as being able to move the camera easily and quickly. Again, these typically do not have very good resolution, but improvements are being made every day and there are expensive models with higher resolution and good color capture.