If one is using a *.cls that requires a graphic file, where should the auxiliary files be so that it works?

I am using the *.cls files from the "Frontiers in *" Scientific Journals. They have their own classes and templates and examples. I put the *cls files in my texmf directory and did the texhash and
now they work. But the class has some logo defined and used on the maketitle command. I have the file, but it doesn’t work if i put it in the same directory where the class file is.

Should I have a copy of the logo files inside the directory where my work is?
I find that inconvenient.