You need an image program like paintshop or graphics gale. Set the grid to 32 by 32, then open a tileset from your game. Copy it, paste as a separate image then delete everything on it. Now paste the parts you want on this and save it as a png, giving it a name to identify it by and put it in the Tileset folder. You can now edit your tilesets in the Database and pick the new one for E and viola, new items.
You can also delete tiles you don't want on your current tilesets and paste some of these in there as well.