newcommand{addInset}[2]{%
    color{#2}%
    typeout{OMG {#1}} % outputs "OMG ../figures/correct_filename.png"
    fbox{includegraphics[width=1linewidth]{#1}}%
} % reports file "correct_filename.png" not found!
makeatletter
newcommand{mycommand}[2][1]{%
% second parameter is a path.
% manipulated #2 with filename@parse and saved the result to baseFileName
defcropfile{baseFileName-moreappendix}
addInset{cropfile.png}{#1}
}
makeatother