A few years back - 2005 to be precise - I uploaded an image to an old Pbase group of tropical looking plant enthusiasts. The image was of the flowering spike of the hardy banana, Musa basjoo. I took it in Overbecks garden at Salcombe, South Devon with my recently purchased Canon 300D and my 50mm f2.5 compact macro. The opportunity arose, a little fill flash brightened the shadows in the flower and allowed the blue of the sky to break through in the background. Not too shabby a shot, though I say so myself. Ah, the heady days of youth.
The other day I was doing some Google image searching to ID one of my insect shots. Out of idle curiosity I typed in 'Musa basjoo flower'. There, first image out of the box, was my shot of this hardy banana.
Click the image and you're taken to the Pbase site of the original upload. But how did it get to be the first image presented? There is no shortage of photos of flowers of this banana.
So I did a little digging. Google reverse image search allows you to drag and drop an image on a website or from your hard drive into the search box of Google images. Sophisticated pattern recognition algorithms then allow comparisons between the dragged image and the Google image database to identify webpages where that image appears. The result is a list of websites. Here's part of page 1.