@Pesala Yes, everybody can do that in some image editor - the point is to eliminate this step. (Not mentioning that the reason we all use Vivaldi is that it supports OUR way of work so we don't need to be lectured on how we should work differently than we do / want, sorry if I'm sounding strict, but...)
Vivaldi is a working tool - a great one, but this would save me lots more of my time, since I'd be able to simply get the result I need directly with almost no effort and just move on to actually use it, instead of getting some middle-product for which I then need to:page capture, take larger part of the screen than needed open a whole new software do the appropriate edit (which on itself is more complicated and time-consuming than just getting the desired result right-away) save it switch out of this editor
...that's lots of work for something what could be easily done with:page capture set fixed ratio, done
Hell, even just SHOWING the ratio would be a great help. (But I guess once you show it, you can also allow to set it...)
Also, I'm not asking for an image editor - I don't want to edit anything.
Vivaldi page capture is (or at least for some time was) one of flag-features Vivaldi team was proud to present. Adding one more sensible function to it is not a sophistication creep.