Showing Texture Arrays in The Inspector

that should show in the inspector you just need the script on something and to turn up the size of the array(in the inspector)

It is shown under the script once you attach it to the object.

Don't forget to initialize the array

var ItemTextures = new Texture[10];

In fact, with the code of yours, you can see it in the inspector and set the dimensions , in size, under the "ItemTextures" fold out. Either way you do it - you will see the slots for textures in the same place, under the script.