My current pains actually involve BitmapFrame classes, so unless that isn't used by WinForms either, you might be up for some pain yet. It is a tried and true disaster, yessir.
For now, I'd be happy enough to be rid of the crashes.
Does the Bitmap.FromFile() call (or whatever) happen to use the System.Windows.Media.Imaging namespace? I think that one is WPF specific, but if it does there might be a solution in there. (I've been hating that one more than plenty so far.)