Help converting avatar to srk size

I have a avatar ready the thing is that srk tells me teh image is to long. i remember that some where on photop there is an option to conver the i mage to whatever srk uses but i forgot how could anyone help me out on this… sorry to sound noob but i am at this. any help little as it maybe be will be appreciated … thanks to anyhone that helps me out :tup: :pleased: