So you're cruising through torrents of images available on the Internet, and you stumbled upon some interesting ones. Be it beautiful landscapes, artworks, candids, instagrams, etc... And you're just itching to know more about the pictures. Where did they come from? Who was the photographer/artist? Where was it first uploaded? Which editing software used to create all the weees and wowwws of that picture?
Welcome to the world of digital images, where a picture speaks more than just a thousand words.
1) First thing you need to check is the filename of the image. Art websites like deviantArt.com and FurAffinity.net has a standard file naming system so that you can track the original uploader of that particular picture.
Filename: [title of art piece; all non-alphanumeric chars replaced with underscores]_by_[artist name, same deal with the underscores]-d[base-36 code].[jpg/gif/png/whatever]
Art page: http://[artist name].deviantart.com/art/[title of art piece, with hyphens instead of underscores]-[the base-36 code converted to base-10] OR http://[artist name].deviantart.com/gallery/#/d[base-36 code]
Filename: [10-digit number, usually starts with 1].[artist name]_[misc. words relating to pic].[jpg/gif/png/whatever]
Art page: http://www.furaffinity.net/[“full” or “view”]/[upload number]
Take this example here, image has the filename life_changing_by_doitforthelulz-d4e1it0.png, which means it was titled "life changing", uploaded in deviantart.com, by the user doitforthelulz
Many other major image hosting sites employ the same system for file naming, you just have to look around and familiarize with them.
2) Now, if the filename isn't that obvious, what else can we look in the picture? Meet our unknown friend: EXIF
Exchangeable Image File Format (EXIF) is a standard that specifies the formats for images, sound, and ancillary tags used by digital cameras (including smartphones), scanners and other systems handling image and sound files recorded by digital cameras. In other words: it's there in digital images.
So, how do we read the embedded EXIF data in a digital image? Go to Google and search for "exif viewer", it will return lots of EXIF viewer applications, including the free ones. Pick one that is suitable for your system. Don't want to download and install another piece of software on your machine, use an online EXIF viewer then. Best example if Jeffrey's Exif Viewer at http://regex.info/exif.cgi.
You can upload a picture or paste a url of an online image.
This picture of a cute cat I just randomly selected from Google Image search:
Returned an extensive EXIF data at http://regex.info/exif.cgi?dummy=on&imgurl=http%3A%2F%2Fwendysiew.com%2Ftest%2Fimages%2Fstories%2Fcat.jpg
Take a look at the link, and see how much details are actually embedded in a digital image. And with nowadays GPS enabled cameras, we can even see the exact location the picture was taken.
3) What if you are actually looking for the sites where the images have been uploaded? Enter TinEye.com, an image reverse look up.
Using the same cat picture from above, TinEye.com listed 63 sites that has been hosting that particular picture of a cat.
So, those are three basic steps of tracking a digital image. You can perform a more extensive diagnose by looking for more tools on Google, but these three techniques would suffice to satisfy daily basic curiosities :)