read and display images using vhdl
there is one book on PLI
"The Verilog PLI Handbook", by Stuart Sutherland, published by Kluwer Academic
Publishers, copyright 1999.
i have not find the ebook version. but has example on this book.
if what you want is to just read/write binary files, you can use verilog2k syntax
mainstream simulation now support v2k now.
if your simulator do not support v2k, find the popular fileio PLI on the internet. it is also a good example on how to write PLI.