MicrostockGroup

I'd say that images that are have backgrounds close to pure white and images that contain both pure white (255,255,255) and light gray areas in the background may get rejected often.

Either go with pure white (255,255,255) or light gray that can't be mistaken for white under any circumstances. Try to avoid anything between.

Then there is always the question about natural shadows. I like natural shadows if they look reasonably good, so I often leave them in the image (they are very hard to duplicate in a convincing way afterwards)

If lit correctly there isn't very much post-processing needed to get the background pure white.

And last: It depends on the use of the image if the layout person wants pure white or not-quite-white background.

Problem with including a path is that (at DT at least, don't know about the others), the path does not travel with the up- and down-sized versions of the jpgs. It only stays with the original. The buyer will not know that. I have (not often) uploaded an .eps with a clipping path though as an additional format.

I agree with this.  All or nothing when it comes to white background.  Even if the images are accepted, they will have more "pop" in a thumbnail if they are pure white.  The almost-white grayish images look a bit dingy in thumbnail.

Also, Vonkara is right, buyers want an image that's ready to use.  With all the selection available in micro today they are unlikely to bother with any image they have to clean up.

I agree, all white or nothing. If you do leave some gray shadows, be certain not to use the keyword isolated, as the gray shadow will cause the image to be rejected. At least that it what I have experienced in the past.

Based on our experiences in the Asian stock photography market, images with pure white background work well for certain design and advertising agencies. But it really depends on the client. Some prefer realistic backgrounds, while others want white background so they can edit the images afterwards with minimum effort.