>Then it's not good for me.

Then you would have to come up with a definition of "file open". If a bitmap is open in any app that can do it, and the file itself is released (i.e. no process has a handle on that file), how is anyone supposed to know the intention of the app's user? The user may have just opened the bitmap for copying into another app, directory, machine or for just viewing. The app may do any of update operations on the file or it may do none. Your app has no means of knowing what the other app's user may want to do. Artificial intelligence is a bit harder to do than artificial teeth.

For me, "technically not open" and "not open" are the same. If any app has opened it and was nice enough to close it immediately has therefore made it possible for me to open it myself. This definition doesn't seem to satisfy the conditions of your case.

So... let's try again. Reformulate your question with your definition of "open", and then we'll see.