My first guess would be an ASCII vs. binary issue. Is your Perl script running on Windows? Are you uploading to a Windows server? If your Perl script is running on Windows, you could try something like

# untested
open my $imagefh, '<', $imageFullPath;
binmode $imagefh;
my $imagedata = do { local $/; <$imagefh> };
close $imagefh;
   my $imageBody = $CONFIGURATION->{filekey}=>[$imageFullPath,$imageFi
+leName,'Content-Type'=>$contentType,Content=>$imagedata]];
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