Beibg near the top isn't as important for image search as it is for regular search, because people tend to scroll down through the page and can scan through a lot of images in a short time. In order to attract clicks, you need something that's different and stands out from the crowd.
Unfortunately, searchers usually just want to see the image and don't click through to visit your site. Another problem is that image theft is even more common than content theft, so if you image stands out from the crowd, someone will likely steal it, and for whatever reason Google usually has no idea who had it first.
Can't stress this enough. For example: If you've got a picture of a widget within spitting distance of a text link to the foobars page, Image Search will think you've got a picture of a foobar-- even if the picture is called widget.jpg and the alt says "oversized blue widget". You may need to tweak things to ensure the picture also comes up in image searches for widgets.
This is probably intentional and not a bad idea overall ("If the picture is called 'stockticker.jpg' how come all the surrounding text is about your escort service?" or possibly vice versa), but it can still be exasperating.
I have a set of photos on line of a concert given in honour of a musician's 60th birthday. The first picture ranks high in photo searches for the musician, however it shows the friend who did the warm up for the concert. Of course every tag and title is some variant of "John Doe on stage at Mary Smith's Birthday Concert".
why do you want to rank on google image these days, you will not get that much visits, be cause the changes they are making to the layout. You just give them content, THEY can use and you will not see over 3% visits, rest stays on google