Images list doesn't work!

Hi!
When I go to my administration panel > Users & Groups > Profiles (Users) and I want to add a new Profile field which is an images list it doesn't work.
This is what I do:

I fill out the fields (correctly I guess). Type: Images list / Name: Country / Display type: Icon
As you can see, everything looks fine and the green "Add" button is visible...


I add 3 times the same image (Argentinas flag) because this is just a test and I choose the first image as a default. The image type is .ico!


I save it and as you can see the field "Country" appears. I click the "modify" button to add more images to the list...


And the list is EMPTY AND the green "ADD" button is gone! Now I just have that blue icon there...


What can I do??? Please help me! I'd like to do an images list so that my users can choose their countries.

My forum: http://missleading.usersboard.com so you can see the version because I am not sure which one it is.

HELP PLEASE!

OKAY I have inserted .png images now and once I save the list with the .png files it actually IS saved and the list appears when you want to "modify" it.
But I am still unable to add more images because the green "Add" button is not there (same problem as before).

How can I add more images?