I have modified editbasic.tpl to remove the option for members to pick what group icons are displayed. I have 4 levels of paid service and of course admin and moderator icons to display. I figured out by using a test user how to force the group images I want, for example:
SQL Query
UPDATE prefix_USER_PROFILE AS up, prefix_USER_GROUPS AS ug
SET up.USER_GROUP_IMAGES = 'a:1:{i:0;s:1:"8";}'
WHERE ug.GROUP_ID = '8' AND ug.USER_ID = up.USER_ID

Will set all users in group 8 (Bronze in my system) to display the bronze group icon (a bronze star).

what I don't understand, but want to, is how to interpret what gets set in USER_GROUP_IMAGES field since I did not study latin crazy

For example:

a:1:{i:0;s:1:"9";} will set a member to silver (group 9)

but

a:1:{i:0;s:2:"10";} will set a member to gold. One has s:1 and the other s:2

Then, if I have a moderator who is also a silver member, it would be:

a:2:{i:0;s:1:"3";i:1;s:1:"9";}
but if he is a gold member it is:

a:2:{i:0;s:1:"3";i:1;s:2:"10";} (again, note s:1 versus s:2??)

Can someone explain how to interpret the different parts of this group image code?

Thanks.