Simsy, you are nit-picking, but never mind. That's the way to improve things.
My front page says, "If you think that you know the program well, have a look at the file called Options.txt in the program directory. You will find a long list of command-line parameters for Irfan View."
That is clearly aimed at experienced users.
On the Thumbnails Options menu, there is an option to save the current size and position. It even remembers if the window was maximised, and the current directory. Have you downloaded the latest verson (3.85)? Maybe the author is listening to you.
I suspect he has made enough money from business users to pay his mortgage. By releasing it free to Joe Public he gets free advertising like this from hundreds of thousands of satisfied users.
One minor flaw I discovered is that if you open a small graphic at the bottom of the screen and then save as JPG or GIF the dialogue box doesn't fit on the screen. I didn't bother to email the author about it. I expect he has noticed by now, or received at least a dozen emails already.
The automatically opened options dialogue is a new addition and the changes this caused maybe got overlooked.