you will always lose some quality when you resize an image but to minimize the effects do something like the following:
if you have a photo of say 1000px wide and you want it to be say 215px wide then - - first resize to either 25% or 50%
- then apply a small amount of unsharp mask (or if you have a later version of PS then use the 'smart sharpen' also in Filters) with an amount of say 10-50% and a radius of between 1 and 4
- resize to the final size of 215px wide and apply more unsharp mask (or smart sharpen)
