Segfaults when trying to open image file with file extension in capital letters

[rtkt]

OPL PC Tools just crashes both on Windows and on Linux.

To reproduce:

1. run OPL PC Tools
2. open games library
3. click "Install game"
4. click "Add Image"
5. select file with name like "GODOFWAR.ISO" and click "OK"

If I rename file from "XXXX.ISO" to "XXXX.iso" it opens and installs successfully.

I created a patch to fix this issue, at least on my NixOS machine.