=====ImageMagick=====
===Resize image===
<code bash>
convert img1_1680-1050.jpg -resize 1920 a01.jpg
</code>
will create an image that is 1920 pixels wide. The height is determined automatically. 

===Create spanning image===
<code bash>
convert a01.jpg a02.jpg +append a03.jpg
</code>
will create a horizontal image suitable for two monitor span. Please note in this example the height of the image will be 1200px which gives us a little problem when applying to desktop.
To append two images together they should have the same dimensions!

===Crop image===
<code bash>
convert a03.jpg -crop 3840x1080+0x0 a04.jpg
</code>
will crop to two full HD monitor resolution (3840x1080), starting at the upper left corner(0x0).