This extension allows you to directly export image data from NetLogo, as well as to Base64-encode/-decode it.
Requires NetLogo 5.0.4 or greater.
Assuming that the SBT executable is on your path, run sbt package to build the .jars.
To build an all-in-one .jar (most useful for use in applets), run sbt assembly and go dig the resultant .jar out of the project's /target directory.
The NetLogo Web Image extension is in the public domain. To the extent possible under law, Uri Wilensky has waived all copyright and related or neighboring rights.