There area a variety of image management tools available to you. You can choose to use on-line resources such as Flickr and Picasa or off-line tools such as iPhoto, Aperture, and Photoshop Lightroom. Below is a brief list of those you might consider.
Some questions you might use to find the right solution for your situation:
NOTE: This is not an endorsement for any one Digital Asset Management (DAM) solution, but a list of the products available to you. For advice on starting a DAM project see the JISC Digital Media page Systems for Managing Digital Media Collections.