Large parts of Imager are written in XS, which is mostly C with some Perl macros. On Win32, XS gets compiled into .dll files. On other platforms, it gets compiled into whatever format dynamically loadable libraries have. You can find out the filename extension for a platform by inspecting the output of perl -V:so on that platform:

Win32:

Q:\>perl -V:so
so='dll';
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Solaris:

$ perl -V:so
so='so';
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