SSS weird behavior with bigger images

ITs weird when I render the image with a smaller size the details on the finger are conserved but when I render on bigger images the details almost vanish, take a look on the images.
I want to the big image have the same details as the smaller one but everytime that I render it look like that.

small image http://imageshack.us/photo/my-images/821/chameleon2.jpg/

big image http://imageshack.us/photo/my-images/20/chameleonhalo.jpg/

please I dont know what to do with this, this is my first render that isnt is a building or something simple like that.

I’m not sure if this will work but try this.
Material > SubSurface Scattering > Scale.

Try changing the scale setting and it might work. Also it has error tolerance so set that to a lower number if you want a higher quality image.

I don’t think it is SSS issue. SSS have nothing to do with Chameleon shadow not projecting on the lit surface side. Deactivate SSS and see if texture and shadow comes back.

What kind of finger texture are you using?

When I deactivate the sss the shadows work fine, Im using a difuse texture and 2 normal maps.
I had tried to change the scale but it didnt change this effect either.
Thanks so far

There are big differences between your images… normal map intensity for the chameleon, some kind of lights or flares in the background, and some kind of mist or DOF maybe you changed some parameters when making the biggest render…
Blender version? …having a blend file will help us help you…
Just to be sure… did you already tried both renders (big and small one) again with the same blend file with equal results?