i created a guest album in category and when i tried to assign that album to guest group it said "this group does not have special access"?
The button "assigned album(s)" on the groups control panel is not meant to actually assign something, but to view the albums assigned to a particular group. That's why it is labelled "assigned album(s)" and not "assign album(s)".
You allow access (to view pics) on the album properties screen. You toggle uploads (on/off) there as well. You can allow your guests to upload or not on the groups panel. However, you can't specify a particular album where only uploads of guests can go to, while registered users can't upload to it (and it wouldn't make much sense). Please read the documentation thoroughly, this is all being explained there.
ok got it thanks for the help.