Well it looks as though the community is opposed to this, I'm not quite sure why. I think it meets our critique guidelines fairly well. As for myself, I prefer the gray background.
You should take a look at this question:
Never use white?
I agree with Scott's answer there but at the same time I think for something as large as a background its better to have something off white. To me, and this could be because of what I was taught in design school, white can often look "unplanned." Unless the rest of the site is exceptionally well thought out and works with the white background then it just looks like you didn't consider the background at all. With your revision, though not markedly better, it shows you considered the background. To me that's an improvement.
That said you should go and fix the images. Whether its a border, transparent png, or some other means. Leaving the white around the images on your new background again shows a lack of consideration.
The condensed version
Its nearly impossible for someone to determine if you CHOSE white or LEFT it white. Picking anything besides white answers that question.