Some of my images removed from Google Image search

why?

[norbiu]

I had 250 indexed images, now I have 170. This happened before. New images keep being indexed every day, but it seems to never get past 250. Is it because I have an index.html page in my images folder to prevent others from stealing my images? I really don't understand.

[piatkow]

My images seem to come and go as well. I have never figured it out either.

[norbiu]

I really don't understand. All my images have alt height and width info, what else is there?