Today I was looking for some images of trees I knew I had, but couldn't remember where on my computer I had put them. I tend to remember what a photo looks like, but I don't always remember what I named the folder, nor where the folder is.
So I opened Picasa, a free photo organizer/editor from Google. When looking for a photo, Picasa allows you to search for photos "by color". Type in color: [color name] into the Picasa search box and Picasa will show all photos on my computer that contain that color. Here is the example below using the color green that I used to find my tree icons. Once I searched by color, it only took a few seconds to find the trees.
If you like the idea of being able to search for photos and images by color to find your photos, you can get Picasa as part of the free Google Pack. You can also use Picasa to Crop, sharpen, make pictures pop.
I seem to have a better memory for color than I do for names, so I find this trick very helpful. Search for any color in this list:
I wish sepia were a color choice, but other than that, the list of colors seems to work pretty well.
The filtering is applied as you type, so as you enter color:b, you'll see pictures that contain both black and blue areas. It isn't until you type color:black that you will see only photos that contain the color black.