This is quite a simple method but I don't know how many people use it. It's the fastest method I know to find stock photos which you usually have to pay for. This method is much faster than searching for images in google, because you are using a stock site's search engine first. Using Google Chrome, head to you favourite stock photo site (i.e. photodune, shutterstock), search by a keyword, order by number of sales. After you find a photo that looks good, right click on it and press "search image with google". Go to tools, multiple dimmensions and get the biggest image indexed by a site who already bought that photo. Using this method I've found photos even with dimmensions of 8000x6000. One more quick tip, despite it's in russian head over to fotokanal[dot]com, and using google translate search for images you need. I think you can use other browser too if you save the photo, and drag-n-drop it into google images. Best of luck!