As a volunteer this is one of the things that I am unsure about, is it better not to upload such images of old headstones, that you need to spend some time in just working out who the gravestone relates to or do you incude it so that someone may add it to their family tree as a document? I tend to decide on the latter course of action as I feel if nothing else it helps someone to find which parish to look up further details. In indexing images I sometimes have to resort to looking at the image through my photo suite and setting it to black and white, which may help you to view this stone.