Photographer Janick Entremont took a portrait of himself, uploaded it to Instagram, downloaded it, and repeated that process over 300 times to see what the photo-sharing service's compression algorithms would do to the image. The resulting project is titled "@facetinction | A (con)temporary portrait."
Re-saving an image over and over and over again in a lossy format (a format like JPEG that tosses some data each time you save/compress the file) slowly but surely degrades the image. This is called generation loss, and it's demonstrated beautifully in these almost painful-to-watch YouTube videos.
Every time you post a photo to Instagram, it loses a tiny bit of quality. It's not really noticeable for a single upload, but if you save and repost the photo over and over, the quality loss becomes extreme. It's a concept known as "generation loss," and is the subject of artist Pete Ashton's project "I Am Sitting In Stagram (2015)."
Recognize the warning message above? It's what Windows XP would show whenever you tried to rotate a JPEG image 90° using the Windows Picture and Fax Viewer. If you're like me, you probably didn't think twice about it (and checked the checkbox), since you had done it many times already and hadn't noticed any difference in quality. After all, how hard can it be to turn a digital photo sideways? You just move the pixels around right?
Well, not really. The fact of the matter is, JPEG is a "lossy" compression algorithm that's geared towards storing and sharing photos without taking up too much disk space. Rotating these compressed images is usually done by decompressing, rotating, and then re-compressing. Since the re-compression is lossy (i.e. data is thrown away), this process results in slightly degraded photos (hence that warning).
"I Am Sitting in a Room" is one of the best known works of experimental music composer Alvin Lucier. In the piece, he records himself speaking, plays it back while re-recording it, and repeated until the words become unintelligible and simply "the pure resonant harmonies and tones of the room itself".