Here's the fun thing about ripping any kind of images from PC-98 games, pretty much every game from different publishers uses a different and most of the time proprietary image format. Hell, sometimes even games from the same publisher as well, so there's no great way to or single tool that will be able to get those specific files out of each game. That being said, there are some options that might help you with certain specific games/types.
I'm going to assume you know how to use
EditDisk or
ND to get your images off the hard disk or floppy disk image files in the first place. If not, you'll need one or both of those. Once there, you've got a couple of options to actually view those image files outside of their games.
One pretty great tool is known as
MLD. It's an executable that you run in DOS in your PC-98 emulator of choice. The basic usage is "mld -c -k filename.ext". -c clears the screen before displaying the file, and -k waits for a key input before moving to the next file (hint: you can use * as a wildcard and say stuff like *.bmp to make it show all of the *.bmp files in the specific folder). There's a lot of supported files in there, so your best bet is to open up the MLDMAN.txt file and look through there. It has a list of the supported files and filetypes.
That won't show you everything, unfortunately though. Your next option is to try to find a Susie Plugin for the images/archives that games support. Most Susie Plugins are for things like VNs, I've found. They weren't super widely supported, but that didn't stop a bunch of people from writing plugins for different image formats. Basically, it defines how to view an image for a program that supports the plugin type. A number of image viewers that work on modern computers support Susie Plugins (
Massigra is one to try).
As for where to find Susie Plugins, I've got a pretty huge archive of them but it's not ordered very well and I don't feel like distributing them, but you can find a lot of them on
Vector, which is a treasure trove of old software.
All that to say, there's no one tool that can do that job for you on this one, really. If none of the above work you can always find out which file is the title screen and replace that with another image file from the same game and make the game display it for you instead of the title screen. We've done that for a number of games now.
