Format for a url that goes to Google image search?

I have a web page which has links at the bottom like this:

- <a href='http://www.google.com/q?rome+photos'>photos of rome</a>
- <a href='http://www.google.com/q?paris+photos'>photos of paris</a>
- <a href='http://www.google.com/q?london+photos'>photos of london</a>

The idea is that if somebody clicks we go to Google search image page and we search for those images of those cities.

The questions are:

1. what's the right URL for starting an image search in Google
2. is there a place in Google documentation where I can find this ? (I searched and could not find it)
3. does Google restrict this type of usage for some reasons?

1. url: https://www.google.com/search?tbm=isch&q=findSomeImage,
2. Nothing official that I'm aware of, but this blog has some documentation.
3. Nope, no limit you should worry about if you're manually clicking the urls. (I'm sure google has some kind of flood protection against bots, though)

So, the only change you have to make, is to add the tbm=isch option to your urls.