First I am not an expert on these cards - many years ago I acquired this one with a collection of others. I've researched the signature and I believe it is authentic. The card is not 100% perfect - on the left side there is a slight flaw - the yellow film on the outer edge of the card has a 1/2" piece missing. It is not part of the photograph. The card measures 6.5 x 4.25. It's 120 years old so I assume that yellowing of these type of paper cards is normal.
Did you know she had 9 children?
The corners of the card are I think awesome. Not bent or chipped away at. Still very round. I've always kept it stored very carefully. This is the only one (exact - signed) that I could find on the entire internet. Probably means it's not the only one but the only one that is for sale. Photographer is LaFayette - London. I'm not always the best photographer so if you need more pictures or details please don't hesitate to ask. I'll give it another shot.
Will ship via USPO with delivery tracking fully insured with signature required.