The smooth smudge effect

Hi I am using the program Photoshop 6.0 (I know, ancient) and I was wondering about an effect I've been seeing around and would really like to learn.

ETA: Thanks everyone for your help!

The effect gives this smooth almost smudged look that sort of blurs the image while still somehow keeping the sharpness and detail. Some examples of what I'm talking about:


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I've tried mimicking the effect with the smudge tool and blur tool but have never been able to make it look like this. I've also looked around and found a program called Topaz which seems to do a similar effect but I was hoping to find a way to do it in photoshop.

Any help would be great! Thanks in advance.