Problem vray

Hi,
i have a problem with v-ray, the light is perfect when v-ray calculate the render but when i save the image in jpg or png it is darker than the preview.

Ok, thank you!

I have another question, do you know why with resolution 800 x 400 pixel v-ray stop working and i read compliying adaptive light?
Thank you very much

Without information to be able to guess, I can only ask you if the model is big, if you have many lights in it or if you open a new file with only one cube in it and try to render, does it still not working?

Ok, it works, i think i had a problem with the file because i imported the model in another file and now it works. Thank you!