Meaning of percentage in image title

Whenever I load a jpeg image into image J the top part of the image says the file name, followed by a percentage in parenthesis. What does this percentage (like 25%) mean? Thanks so much!

Hello Christine.

ImageJ will scale image windows to fit them nicely on your screen, try clicking + or - on your keyboard with the image selected and you will see this number change.

Note that measuring this box, which is the same for both pictures, will give identical results.