As you may have noticed, images are what I have most of. ^_^ I've scanned all the covers and inserts of each manga, as well as the best scenes from each. There are 19 manga volumes available altogether, and the series is now finished.
I'm lucky enough to own the Jiraishin 1999 Calendar, and have scanned all the images from it. The artwork is gorgeous! I have several of the pages framed and hanging on my walls.
I also used to scan a few pictures each month from Afternoon magazine, when Jiraishin was running in it; the paper quality is not as good as the bound mangas, so the scans were sometimes a little grainy. As each story made it to manga form I rescanned them and took down the Afternoon images; however I have kept up the extra colour pages and ads because they're cool. I no longer subscribe to Afternoon, though -- without Jiraishin, it's just not the same. ^_~
There are two 'special' volumes released seperately, called Memorial Collections. Each one is the size of Afternoon, rather than the smaller size of the manga, and each is a reprint of an earlier volume; Memorial Collection 1 is a reprint of volume 11, Mother of Crime, and Memorial Collection 2 is a reprint of volume 15, Murder "A". The first one includes a poster, postcard, and a long interview with Takahashi-sensei. The second one includes a postcard and a gallery of other wellknown mangaka drawing their interpretations of Kyouya and Eriko. (So cool!) Since each of these is a reprint volume, they're only worth getting if you're an obsessed Jiraishin fan, like me. ^_^ However if you don't have volumes 11 and 15, you may be interested in getting the Memorial Collections instead. Try asking at your local Japanese bookstore -- unfortunately they don't have ISBNs that I can find, so you'll have to ask for them by name. (The publisher is, as always, Kodansha.)
In my next life..