Hi Nofi,
That is a difficult question to answer without knowing more about your camera/peripheral. Does it have any sort of standard-looking bus interface pins (read/write/address/data)? Is the timing for the peripheral constant for each access or can it vary? Does it have internal memory or is a collection of registers where you repeatedly read a data register to get the images?
These will affect whether the best way to hook it up is merely with the component editor and some avalon signals going directly to it (simple), or whether you'll need to design some interface logic (more complex) and then make that a SOPC Builder component, or whether to use a very simple architecture like a collection of PIOs as you mention (very easy, but slow).
These sorts of things will infuence the best way to hook it up.. please let us know more about it .