property CalcCombo.PictureDown as Variant
Specifies the picture that's displayed when the button is down.

TypeDescription
Variant A Picture object that indicates the cell's picture. ( A Picture object implements IPicture interface ), a string expression that indicates the base64 encoded string that holds a picture object. Use the eximages tool to save your picture as base64 encoded format.
Use the PictureDown and PictureUp properties to specify the picture for the buttons. 

The following sample assigns different images to the buttons:

PictureUp = "gBHJJGHA5MIgAEIe4AAAFhyFiC9fa9bDbbABjEZjUbjkdj0fkEhkUjkklk0nlEplUrlktl0vmExmUzmk1m03nE5nU7nkihgAEL5AgBhj/AAsn8JpRABCZAD/BIcJCwUDBQYIAIILDIWChYaHAACEh8JCxMTERIVGYyXiIeAfQCPEBDRQMbJRUBCRoaHIaHiJaSiYiSGBjZScBKTMpLRAdNreNioWSgZydBZ7CT8BJUdBAUQ7RoODrJKjkJaaKCjJSdJQVFJKAAlVq2KjqCIoYinHy9HTkVT1FTYUJiPKeHqaOzjLSTNqDXztDSXNhcAJcdKKZo7GCAb6/QADf6lJS4GDCQAAHcBA"
PictureDown = "gBHJJGHA5MIgAEIe4AAAFhyFiDYiQBikVi0XjEZjUbjkdj0fkEhkUjkklk0nlEplUrlktl0vmExmUzmk1m03nEhhgAEL5AgBhj/AAsncJoxABCCAD/BIcJCwUDBQYIAIgLhICBAQCEBgjHSEDBxcJERYAGRqbjIKKjYiKCwfDxUBByUjISQoKaqUi4eQfZKRFoFLw0fBycrMQQ1KreNgYablv4dQZyfjZWaoaKjEBzSxUZQzczOQJMS4SQraeapZiqKavHTNdQSFZLTZcUYmBrreorJSrAoDVBdZa2dpaUhwMYGAgAHcBA=="