What unit of measure is dimension of a JPEG file stated in?

Answer 1

two dimensions for jpegs - first is pixels for the width and length - you can also get the area of the jpeg by multiplying the pixel length and width which is called the megapixel size the second measurement for a jpeg has to do with the way it is compressed - for compression the image is broken into squares that are several pixels per side then the those squares are processed to decrease number of colors etc to make the file size smaller - the number of pixels in the squares and the amount of compression in each square is determined by a percentage number from 1 to 12 with 1 being the highest compression and largest squares to 12 with no compression and no squares - if you ever look closely at a jpeg you can see the "squares" in it