I am using a 2.1 megapixel digital camera to take pictures of medical products. The pictures come out gorgeous, but when I try to make thumbnails and start reducing it's dimensions, the pictures start to get extremely blurry. Now I know that you are supposed to reduce them in increments. And I do sharpen them here and there while I'm reducing the image dimensions. What am I doing wrong?
I am not sure what size your starting with and what size your going down to?
If you start with an image at 1600 x 1200 pixels and reduce it down to, say, 64 x 48 pixels; it will not look sharp. Your best bet is to use an original image and a thumbnail image.
Place the thumbnail (no larger then 100 pixels on any side) on a page with other thumbnails and text. Hyperlink each thumbnail to the orignal image, so that if a person wants to see a more detailed picture, he or she can.
You can see many examples of this at most e-commerce sites.