Hi Dave. Merry christmas.
Try this software.
The maximum width so you wont need to scroll across is approximately ~ 880 pixels.
600 is standard.
You can download a picture resizer from this site for free.
It is freeware with no bundled up crap or ads with it.
I use this software for all my conversion and resizing.
It will convert different formats to Gif - jpg - bmp - png
Some of the more common picture formats.
jpg being the most common and smallest.
It can be downloaded right to your desktop and you can set the size to anything you like.
Scroll down the page for picresizer 2.02