use MIME::Base64 qw( encode_base64 decode_base64 );
open( INBIN, '<', 'file.png' ) or die "$!";
open( OUTB64, '>', 'file.b64' ) or die "$!";
binmode( INBIN );
while ( read( INBIN, $buf, 60 * 57 ) ) {
    print OUTB64 encode_base64( $buf );
}
close ( INBIN );
close ( OUTB64 );
open( OUTBIN, '>', 'out.png' ) or die "$!";
open( INB64, '<', 'file.b64' ) or die "$!";
binmode( OUTBIN );
while ( <INB64> ) {
    print OUTBIN decode_base64( $_ );
}
close ( OUTBIN );
close ( INB64 );