Issues with changing the game window size

Hi, this is my first day using the RMVM and I'm a total newb. I wanted to change the size of the window from a square to a more standard wide format so after poking around I found this:

Graphics.width = 1920;
Graphics.height = 1080;

I then added it as an event > Parallel Trigger > Script and it sort of works but I'm running into some problems.

1. When I first launch the game, I can press F4 to go full screen with the desired size of 1920x1080 however, the map does not entirely fill in but instead it seems to want to retain the original size. When I walk, it does indeed extend the map sort of in the way that "fog of war" is removed when exploring in an RTS game. The odd part though is that when I walk back, the fog of war (black area) returns as well. Odder still, when I trigger a combat event, then return to the map, the entire map is filled in as intended with no black areas. How can I get the map to be entirely filled in when entering the map without waiting for a combat event to make it "stick"?

Before triggering a combat event:


After triggering a combat event:


2. This leads to another issue. Having set the window to 1920x1080 is breaking the combat window as it wants to fill in the entire wide screen whereas it seems it was designed for that default square. Is there a way to resize the combat screen to the original dimensions yet retain the desired window size or will I need to use a larger background image?

Broken background in the battle window (note the black):


Broken background in subsequent battles. It's the same as above except in this case the black is filled in with the map as mentioned above.

In addition to the issues above. I also can't seem to use any sized image for the title screen other than 816x624. I'm currently working with a 1600x900 window and with the game launching in full screen rather than windowed but any image in the titles1 folder that isn't 816x624 gets ignored when selecting which image I want to use. How do I get RPG Maker to list all title images and not just the small ones?

I also tried importing the image using the resource manager which works and even appears within the resource manager titles1 directory but it is still not listed when trying to change the title image under system window. How can I fix this?

Yanfly's Core Engine is the best way I've found of resizing the display. There's also a plugin that comes with RMMV but it doesn't scale the tiles to new window size so I'm not a big fan of it.

http://yanfly.moe/2015/10/09/yep-1-core-engine/

2D works differently than 3D, and one of the effects is that everything needs to be resized manually.
you need to use an image program like gimp or photoshop to resize the pictures for title or battleback to prevent that effect, and also the screen size becomes the minimum map size - you'll need larger maps if you set the screen size larger.

there are some scripts that zoom instead, but zooming creates fragments and distortions that reduce quality, so the better way is to resize the images.

@Frogboy Thank you very much, that was a quick fix. :)

@Andar Yes I understand. The images I've imported into the titles1 folder were in fact new images that fit the new resolution (I've played around with several 16:9 resolutions). The issue is that RPG Maker simply does not recognize these new title images and therefore will not let me select them as an alternative title image. The plugin suggested above works very well for my first two issues and well enough for the title image too - it scales the image to fit my specified resolution but this is still an imperfect solution as I would like to have images appear as designed for the resolution I'm working with as they are going to look sharper and with the correct aspect ratio.

Edit: I resolved my third issue relative to unrecognized title images... I had imported a .jpg instead of a .png. I'm just going to pretend that didn't happen.