It crashes when I try to open a file (image or palette). The browse window opens, but img2pixel shuts shortly after.
So if I understand you correctly, img2pixel crashes before you close the browse window, right? That would mean it crashes inside your OS, since img2pixel doesn’t do anything while a file dialog is open. Is there an entry in the windows event viewer (“Windows Event Viewer” => “Windows Logs” => Application) about img2pixel?