Google images isn't likely to show or index all your images. If you notice the normal thing (web search) has more than 6,000 results. Take for instance this website, site:junkstr.com. We have more than 40K pages indexed but the Google image search doesn't show anything close to that.
There are a few things that we can improve like add the image description as the alt attribute but at the end the thing is that Google image search is a different thing.