in reply to Is it possible to use modules without installing them?
In general, if the module concerned is a "pure perl" module, there is nothing (provided you take the copyrights etc with it) of including it into your script as source.
However, many modules have XS and/or C components and they obviously won't work without their compiled bits.
I'm not familiar with the internals of GD so don't know which is the case for it.
Being a graphics module, it's quite likely that at least some of it has been optomised to C for speed?
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