Noise reduction after resize and conversion to jpeg?

I shoot at 100 iso sometimes and think there's no need to use noise reduction and my pics look great in full size Tiff when I take them in to an editor. But, after resizing down to 1024 or around that, and converting to jpeg to put on Flicker, my pics then appear to have fine grain in them. Like this one.

I saw a while back someone explain that resizing makes the pixels smaller and puts them closer together or something to that effect and this can make thew pics then look grainy for use on the web.

Can someone explain all this, how this might happen and if noise reduction should be used after resize and conversion to jpeg, or when I should do noise reduction to avoid my web jpegs from looking grainy?

Thanks much.

HTTP response: NOT FOUND | MIME changed to 'image/gif' | Redirected to error image by FLICKR

Noise is random variation of light between pixels. Resampling basically averages and removes the noise.

How are you resizing? Bicubic Sharper? Image looks a bit oversharpened. Try another resampling method, or try this: http://manyk.deviantar​t.com …ng-in-Photoshop-214143878

As for ISO 100, you might still see some noise in the black areas because they're "underexposed". And who knows what processing Flicker is doing, anyway?

It seems to me that you'd be better off using NR on a duplicate layer of the full size Tiff. Then look at it after you've resized it & see what you think.