ExactImage is an image processing library which reimplements ImageMagick 
functions with a significant speed improvement.  The library also provides 
several new algorithms: lossless JPEG transforms and creation of searchable 
PDFs from hOCR annotated HTML. There are bindings for PHP, Lua, Perl, and 
Python.  See /usr/doc/exact-image-*/examples/ for information on using 
exactimage with Perl, Python, PHP and Lua.

This requires agg.  lua and evas are optional dependencies, as is bardecode, 
but bardecode is not available from SlackBuilds.org.