Take a look at the IP Home Security Cams. Amazon has a variety of models from less than $100 up to more than $300. I have used both the TriVision and a Sharx in similar setups.
The "Trivision NC-335PW HD 1080P Waterproof Bullet Home Wireless Outdoor Surveillance Camera System" might be very close to what you want. I am using that camera, a wifi router and a Raspberry PI in a homemade alarm. I have them running on ac power with a APC battery backup. The camera is there to record motion and allow a look at what is in the field of view, and the PI is talking to a weather system that is tracking indoor & outdoor weather conditions, water flow and humidity. The PI is there to also sound an audible alarm under some conditions.
This type camera will take photos, video or both when it detects motion or on timed intervals. It does night time images but if it is outdoors, the IR LEDs might attract a LOT of insects.
You can have the camera hold images until you retrieve them, ftp to a server, send to a Dropbox account or send an alert to a iPhone. You can also watch live from a remote location. You can get a camera that allows you to pan, tilt and zoom from your remote location.
I have never checked to see how long the APC would support this setup but I know that it will last at least 30 hours.
CarriGo
Model 2320