On the Australian Ancestry website Walter is part of someone's tree. Be aware that he is referred to as William Walter not Walter etc.
If you are able to access the Australian Ancestry you may be able to contact the owner of the tree and ask about any photos. If not pm me and I'll see what I can do for you.
The birth record of September 1863 shows the names as Walter William Giffard TATE.
Edit - Just realised that you are in Australia! If you are not the owner of the tree then you can try getting in contact.
If you are, have you traced any descendants from Walter's siblings? Have you considered putting this appeal on the Australian section of Rootschat?
2nd Edit - Been having a poke about on Find My Past and found that Walter known as William had seven siblings. Dad Francis died in 1867. Francis married Emma GIFFARD in 1848. So there is quite some potential for descendants who may have a photo!!
At least two other siblings seem to be referred to by one of their other names - Francis/Alban, Hannah/Maud. All the family are on the 1861 census in Axminster, Devon except for Walter/William.
