Warlords 3 (and to some extent the Battlecry series) has some of the most gorgeous game art i have ever seen in a fantasy game.

I'm talking about the icons for everything, from buildings to units and heroes.

Did anyone ever manage to extract the images from the game files? I had a quick glance last night hoping it might be something straightforward but it doesn't look it.

I would love to see the images in higher resolution and maybe use some for icons/wallapers.

Actually it's fairly simple. All images are stored as .pcx files in the respective folders, for example images for heroes are stored in the HERO folder.
I remember Windows 95 had an image viewer for pcx, I guess that got lost along the way.
But pcx is still supported in some of the more sophistcated image editors, you can check wikipedia: https://en.wikipedia.org/wiki/PCX or use paint.net with a plugin: https://forums.getpaint.net/topic/2135-pcx-plug-in/

Warlords 3 images are in PCX format and can be found in appropriate folders (Hero, Army,Terrain, Picts etc).

PCX files can be read and coverted to PNG, JPG, BMP etc in XnView or IrfanView, both free software.

As for Warlords Battlecry 1-3 you need a free program XCR Editor to open XCR archives where images are stored, in appropiate folders too (usually named Graphics, Portraits etc). XCR Editor allows you to view and extract image files that are stored there in BMP format IIRC.

XCR Editor can be found here:

https://etheria.fandom.com/wiki/Tool_Downloads

There are too many watermarks there :)

I got my little collection of A. Lockhart art from there:

https://www.theloop.com.au/alisterlockhart/portfolio/Creative-Art-Director/Sydney

and from some other source I can't find now (maybe that site is gone already).