Hello,
If you create an ImageCellType in a cell, then you can set the HorizontalAlignment and VerticalAlignment properties on the cell to align the image. It is working correctly at my end with the latest version of Spread for Winforms i.e. Spread.Net7 v2. I would suggest you to test the issue with the latest version which you can download from the following link: http://www.componentone.com/SuperProducts/SpreadStudio/
Hope it helps. In case the issue still persists I would request you to provide me with a sample application depicting your issue.
Thanks,
Manpreet Kaur