| One of the most popular social media sites being used by multiple generations from Baby Boomer to Generation Z, is Facebook. Facebook was founded in 2004 by Mark Zuckerberg, who was attending Harvard University at the time. While the site was initially designed to serve as a social media outlet for college attendees, the utility of it quickly spread to the common public, where it became a means of connectivity for individuals, regardless of locale. Today, Facebook has connected families and friends separated by varying degrees of distance in the past with about 250 billion photos uploaded by its users, averaging around 350 million uploads per day. With having to host this significant amount of photo images, Facebook compresses uploaded images in order to reduce the file size, as well as saving on storage [10]. The downside to the compression is that it leaves images, specifically JPEG (Joint Photographic Experts Group) images, with poor quality and creates compression artifacts which are noticeable distortions on the images [12]. JPEG or Joint Photographic Experts Group, are images that have a lossy compression algorithm which means the image compression rate can be adjusted to size and image quality. Since JPEG images are adjustable, they are also susceptible to alterations and manipulations. To investigate whether a JPEG image has been altered or manipulated, effects of the DCT or Discrete Cosine Transform on pixels and ELA or Error Level Analysis can be used to analyze the image. This paper will investigate a combination of images that has been altered through Photoshop as well as Photoshop images compressed by Facebook. Since Facebook compresses JPEG images at a high rate, the question is whether the manipulation can be visually detected or not through DCT or ELA. Working with both analyses, the results should illustrate which method results in better quality and easy detection. DCT map provides better visibility than ELA where an object was removed in an image. Although after using Facebook, the results of the tampered area on the image cannot be detected using DCT map. |
