Here is an image to use when recoloring high chairs. It has a transparent background, so you can easily use it with any recolor. It is very close to the Maxis original.
It's a .png file, so it should work for most people. If you need it as a .psd (Photoshop format) instead, let me know by PM.
DO NOT download the image shown in this thread. It's a .jpg and does not have a transparent background.