i think something is messed up, I uninstalled and deleted the them, and then I reinstalled it and the original twitter icon did not change at all to the icon that came with the theme, it seems like the only icon that didnt change, all the other icons changed fine.
Do this. Unselect your theme in winterboard or delete it.
Go to the original twitter file in the path I gave you above var/mobile/applications/twitter....
View the file properties, ownership and access permissions and make sure your new file matches. Change the name of the original file by adding a 1 behind the name i.e. icon1@2x and then insert your file, making sure your file name exactly matches the original.
And you are changing the icon with @2x after it, correct? And your icon is roughly 114x114px in size?