Have you tried a totally different folder with totally different images? Do you get the same reaction?
Have you tried making a new folder, but adding only two images to that new folder at a time, and testing the images after each two?
Have you recently downloaded and installed a new version of Qimage? If so, try turning off the Anti Virus, and download a fresh copy and install.
Fred

Had already done the things that Fred suggests.  This appears now to happen anytime I make a change to an already existing filter. Then the thumb wont show up, rebuilding thumbs causes all the thumbs not to show (in that folder) and then as long as I wait until Qimage crashes, I am ok until I change another filter.  I have re-installed Qimage but that didn't help.  Clearly, some component of my Qimage installation has become corrupted, but where?.  I looked at the ini file and it looks OK, but I am not an expert there. I might add that I printed a bunch of photos last night with no problem.  Funny thing though, about ten minutes after the last print finished, - and the computer was sitting idle (I was across the room sorting though the prints), Qimage crashed. Wierd stuff. I'll figure it out eventually - but appreciate all of your suggestions.

This sounds an awful lot like the symptoms caused by an antivirus/antimalware program.  These programs love to open files at inappropriate times and/or lock them so that other software can't get to them.  I would suggest making sure you have a copy of your antivirus and/or anti-malware programs ready to install and then uninstall them temporarily to see if it fixes the problem.  Entering exclusions, exceptions, or even disabling them often doesn't really disable or correct the problem unless they are uninstalled.  So if you can uninstall/reinstall without too much trouble just to test it, I'd do that.

The second thing is that Windows 7 media center and Windows Media Player now have no clue how to properly handle file I/O.  If you've set up your Windows Media Player library to monitor the drive/folder that contains your images, this can cause problems with just about any app.  Basically, as soon as any file is changed or added in a folder that WMP is monitoring, WMP starts opening those files in exclusive (read-only) mode, screwing up other operations that the program which created that file may need to perform.  Of course, like most programmers supporting Windows 7, I've modified Qimage to know about and handle those situations but Qimage is only one of many programs (like the antivirus/antimalware programs mentioned above) that need access to those files.  So the final test if you still have trouble without antivirus/antimalware running is to try working with photos on a drive (and folder) that you have not added to your media library.

Those are about the only things I can think of that can cause the strange problems you mentioned.

Mike

Thanks to all of you.  Each of you has said some things that are not exactly like my sitation, but close enough to give me some things to fiddle with. I will report back - and/or update information as I work through this.  Thanks again.

I'm pretty sure there are no other  files updated when you make or edit a filter.
When Qimage shuts down the qimage.ini file, which remembers your current settings, gets updated I believe.
For XP that is located in C:\Documents and Settings\All Users\ddisoftware\Qimage
You can browse to it from the Utilities menu (take care!) which OS is being used - browse to Application Data.
Terry.

OK - thanks - so - are there any other files updated?  No logs or other tracking info?  What does Qimage do if the thumbs and the filter and or image file are out of sync?