I did test on a mix of .tiff, .jpg and .png and had no issues, but that was on the 10.6 system I used to build it. I just tested on a PPC 10.5 system and it crashed on a tiff and a PNG file.
Ok, back to work for me. It is puzzling, but hopefully I will figure the cause out soon. It must have something to do with how the supporting libraries are linked into the bundle. I don't know why JPG works, but life is full of mysteries.
As to other apps launching on their own, I am very puzzled how that could be - I haven't seen anything of that sort and don't know what could possibly cause that. More mysteries.
And, I just compiled all libraries fresh, and made them all "static" so the ScanTailor app didn't have to worry about which version to call, so the application only has itself (with all the other parts bundled in) and the Qt framework, and it still dies.
If anyone wants to send the crash report over, PM me for my email. It doesn't look like this is in the ScanTailor code, or in the stuff I'm compiling, but somehow in the Qt libraries themselves:
Exception Type: EXC_CRASH (SIGABRT)
Hung on: QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>)