In classic windows it was more grey and, indeed, as you admit: less distracting. It is Windows 10 (and Vista to a lesser extent) that introduced the white color of the UI 'chrome'.

Classic UI presents elements in sorted order, enabling to tell at a glance a toolbar from a textbox or content, which is a 'display panel' inside the chrome. The flat Windows Metro interface is not good, if you compare both visual styles by merit, disregarding that one is new and trendy, and other is from the 'past' and 'antiquated'. Those programs that do away with 3D elements look broken on Windows classic: panels and buttons have inconsistent height, sometimes cut off on one side like in those optical illusions that present physically impossible shapes. I would like the complete border to remain an option. Can we please get the first option at least in order to make it more Windows 10 friendly? I'll fully switch to IrfanView if I don't have to see uneven white borders on images. Those are two highly valid ways to present images as cleanly as possible, and seem like good goals for IrfanView. What would really be incredible is having two things: A default mode where the border works correctly as seen on the right, and a mode where there is no border whatsoever. White is more distracting than black or dark grey. That goes for most professional video and photo editing software, and there are great reasons. Think of how internet browsers and Photoshop also abandoned white areas surrounding images years ago. Many projects I know of still being updated have done away with it, especially video and image viewers which people seriously use to admire beautiful content closely. I can say for sure the Windows 10 GUI did not plan for programs to keep using this approach which probably dates back as far as Windows 95. The fact that the left and right edges are not even remotely similar is a distraction unto itself. You have grey on one side, then bright white lopsided edges. It is a distraction rather than an enhancement, and I'd like to emphasize how noticeable it is fluctuates all the time based on how dark the surrounding area is and what each image looks like. It could seem small to you but means a lot to me. The question which I think is worthy of asking is why do we still hold onto these? I'm very sincerely requesting that you consider this because I've tried to be as thoughtful as possible in how to present it and believe it or not have really wanted to for years. Modern Windows' border is only one pixel, thinner even than IrfanView's. The time it was intended for must surely be past. Well first of all I apologize if I should have posted this in feature requests, though I almost consider it a lingering bug in the following sense: It maybe leftover from older, or even much older Windows builds where it was far less noticeable and considered to work well enough with their border thickness.

Windows 10 border size