Lacy ancestors, Indiana 1800's

I have really no info on my Lacy ancestors, although I do have pictures of them. When asking around the family my great uncle said the pictures were of his greatgrandma & grandpa Lacy, he doesn't know their first names, as he only called them grandma&grandpa. All we know is they are the parents of his grandma Ida Belle Jackson (my gg grandma)He says she had half siblings named Bob, Jim, Grant,and Johnny.I know this is not much to go by, but if anyone recognizes these names please help, Im at a dead end. Ps Ida Belle Jackson &husband David lived in Vermillion Co, In. when my gma was born in 1896