hi, sarah
exif data is invisable but travels with all digital photographs, it stands for "Exchangeable image file format."
exif data cannot be changed, it records time photo was taken, lens used, iso, f-stop etc., it also records location via satellite if the camera supports it.
a couple of your photo exif data says the photos were taken
february 27th 2005 just after midnight 12:44, 12:48 AM
metadata is also invisible data information that software or you can add to the photograph. all news agencies use exif & metadata information and there are standards that are used internationally
what is throwing me off is the exact rectangular pixels that have a portion removed (upper right hand corner of ur circle) at the very same spot in 3 of your photos. btw, how did u draw the circle? what software? photoshop elements?