If you have Adobe Photoshop installed and you have a DSLR camera that records actuations, you don’t need an EXIF reader to find out the number of actuations on your camera.
With your photo open in Photoshop, go to File > File Info then scroll to the right to get to the Advanced Tab.
Expand the 4th item on the list = Schema and look at the aux:ImageNumber entry. The number you see is the total number of actuations as of the time that photo was taken.
But if you have a Mac, you’ll have Preview installed by default, and all you have to do there is to load the image in Preview, go to Tools > Show Inspector. Click on the Exif button and scroll down a bit to where you can see the Image Number entry.