We are trying in unity 7 to upload a file in the OS Admin in call manager. Does it still need to be 320x212x12 and a .png file? or does this work differently now?
depends completely on phone model and it's for CUCM, Unity has nothing to do with this
go to CCO and search ie 7945G IP Phone Administration guide
you will get the link, click on it and on left hand customizing the ip phone.
background instructions and requirements are there.
change the model for what you have
if this helps, please rate