How to alert the pointed image when rotation stops on it?

You're going to do a little bit of maths.

First, work out what angle your bottle will finish at, from 0° to 360°.

var clamped = deg % 360;
if (clamped < 0) { clamped += 360; }

Then, work out which of your images that equates to. You have 10 images spaced equally around the circle, so a simple solution is to divide the angle by 36 and floor the result to get an integer.

var index = Math.floor(clamped / 36);

Math.floor() - JavaScript | MDN[^]

Because of the way you've arranged your images, index 0 equates to the number 6; index 5 equates to the number 1; index 9 equates to the number 5. (You don't need to worry about index 10, because the angle will always be between 0 and 359, so the index is always between 0 and 9.)

var number = (index < 5) ? index + 6 : index - 4;

You now have the number that your spinning graphic will end up pointing to. What you do with it is up to you.

NB: There will be some odd-looking cases where the bottle is pointing between two numbers, and the code picks one of them. You might want to work out a way to put a "buffer" between the numbers that doesn't class as either of them.

Updated fiddle[^]