There's a low tech way to make units 32 pcxs.
Play with the unit in the game, take a screenshot, and cut a more or less 32x32 slice of the screenshot, resize to exactly 32x32, then paste it into the units32.
I use something I downloaded for free called "Image Forge" (I found it doing an internet search for "pcx") to do screenshots and cut and paste and resize. I just hit the print screen button during the game, close the game, open Image Forge, select Edit, then Paste, then As New Selection, and there it is, the screenshot as a new pcx file. From there I can cut out a rectangular part of it, and paste as New Selection again to make a small file, then I can select Resize and put the size I want it. Then, depending on what I'm doing, I use Gimp (which was recommended by a post somewhere, and is also free, but is fancier than ImageForge and kind of hard to figure out how to download and install) to open and close it which gets the save format right since imageforge can mess it up so Civ won't use it, especially for Terrain and like Tech Icons, but I think its OK for Unit32s.
And if you aren't about to download a free graphics program and learn how to use it, you can just substitute a units32 from some mod that used a huge one with almost everything, then reset all your icon selections in the editor to use something that's kinda close to what you want. Sometimes, inexplicably, units32s from mods don't work in other mods, though.