\pagestyle{fancy}

\fancyhead{} % clear all header fields
\fancyfoot{} % clear all footer fields

% Define headers and footers for regular pages
\fancyhead[R]{\includegraphics[width=0.82cm]{logo_small.pdf}}
\fancyfoot[C]{\thepage}

% Redefine the plain page style to be used for the first page
\fancypagestyle{plain}{
  \fancyhead{} % clear all header fields
  \fancyfoot{} % clear all footer fields
  \fancyhead[R]{\includegraphics[width=4.5cm]{logo.pdf}}
  \fancyfoot[C]{\thepage}
}