I resized an icon from 128x128 to 40x40 pixels. The snap-to-pixel option is turned on, but the icon is still "blurry".
How can I resize my image and retain sharpness?
This is one of those cases where it's a good idea to plan things out beforehand and do some math. There is no way to take a 128x128 image and reduce it to 40x40 such that your lines will end up as whole pixels, nor aligned with pixel boundaries. You also can't take a one-pixel line, reduce it to 40/128 (5/16ths) of its original size and still have a one-pixel line that's correctly scaled. Your individual calendar "boxes" are 31 pixels wide by 16 tall. They would have to reduce to 9.6875 pixels wide by 5 tall. That's impossible, so FW has to fudge it.
The 26-pixel top banner has to scale to 8.125 pixels, which throws off all your horizontal lines, because FW can't put them on pixel boundaries and maintain proportions. FW has no choice but to try its best to approximate, using whatever algorithm it's using to throw away pixels, the appearance of the original. It doesn't do a great job, but you're giving it an impossible task.
If you start at 160x160 and reduce that to 40x40, you have a much better chance of getting an acceptable result, but you have to work with multiples of 4 pixels to get the best product. To get a clean 40x40 icon, I would create it at that size to have pixel by pixel control over placement. Use this trick to make it easier to work with.