When you resize a large, sharp photo to a smaller size you may find that the new image has lost its sharpness. This is a common problem with changing the size of large, clear images. The blurry look can detract from the quality of the image.
Fortunately Adobe Photoshop has the ability to fix this issue with its advanced editing tools.
This method will only work in Photoshop CS and CS2. These versions are more powerful in a lot of ways, so if you don't have them I'd recommend that you invest in a copy as you may find that you will need the more advanced features.
To reduce the size of an image go to Image Image Size. Select Resample Image and then select Bicubic Sharper from the menu. This is the optimal setting for reducing the blurring of the image when you resize it. Here is an image of an eye that was originally 1800 pixels across.
I reduced it to 250, and then further to 125 with minimal loss of sharpness. If you want to enlarge a photograph without losing too much resolution select the Bicubic Smoother.
This method is extremely effective in keeping the sharpness of the image. You can set this as the default to make things easy for you by going to Preferences General where you will see Image Interpolation. Select Bicubic Sharper as the default choice and it will be set as the default from now on.
Remember that performing more than one resize on an image will give it more blur. To experiment with the size that you want, use a duplicate image as multiple resizing will ruin the original image. Once you've found the size you want, you can apply the dimensions to the original image