The IPOL Journal has been around since 2009. It is one of my first exposures to processing. This may fit into my never ending G’MIC exercises thread but I have decided to make a new one, just as I did for Kovesi’s functions, in case you missed that one.
The great thing about IPOL is that every paper (article or preprint) is categorized and comes with a demo and an archive of code. Start with Getreuer’s because his is all in one place (or maybe not since it goes up to 2013 only).