By default, X3 sorts images as they are stored on your server, which is normally server creation date. Currently, you can only set the following in gallery settings to reverse sort:
Code
sort:asc
Code
sort:desc
Some time soon, we will be providing additional sorting methods, so you can also sort by name.
Well, there is no "chaos" setting in X3 unless you are using the "shuffle" tag. 100% I guarantee you files are sorted how they are stored on your server or by naming convention. If you can give me link to your gallery and FTP login, I can prove it to you.