You have to write
your own sort (click here) in which you parse the number out of the name and sort by the number.
BUT
If you can, easiest way to get around this problem is to save the images as 01, 02, 03 etc...then string sort will work as expected.
The cause of the problem is that string starting with 1 like "10" is in string comparison smaller then "2" since it starts with "lower" string value.
Similar to how you order
yellow
yellowstone
yolk
even if yellowstone is longer then yolk, it is compared y = y, e < o...
between yellow and yellowstone, the comparison goes to w = w and then "" < "s" so yellow goes first.
If this helps please take time to accept the solution. Thank you.