Am surprised no one can resize pictures.
Windows 3.1, 4, 5, 6 and XP come with paint program.
XP - in accessories is mspaint.exe
Just "run" mspaint, load picture, select pic, and select stretch. Default is 100
%. Just change % to 50 an 50 x+y axis, or whatever reduction is required, and job done.
Win 3.1 to 5 was paint.exe.
I use Paint shop pro 3.12 32 bit ( free one ) and works on most computers.
if you have not got "paint" on your computer, load CD instalation disk and "add" extras.
Also remember that not everyone has a 3 mile wide screen. Mine is 14 inch at 800 x 600 resolution, but you can always do 2 photos. one at 800 x 600, and one at silly resolutons of 1600 / 2000 pixels.
Why have i not got a wide screen ? - because the text and pictures show smaller, the higher resolution you go, and web pages now use the extra space on the right for adverts, - which i dont want to see and am not interested in.
( I decide what I want to look at to buy, -- and not a web site )
A4 portrait paper is 210 x 297 mm ( 8.2 inch x 11.6 inch )
A4 Landscape paper is 297 x 210 mm ( 11.6 inch x 8.2 inch )
Portrait photos on A4 = 787 pixels x 1113 pixels
Landscape photos on A4 = 1113 pixels x 787 pixels
So having photos any larger than this if you print a lot, seems pointless, but a larger picture fits on larger screens.