图像未在添加到自定义列表的项目中更新

I have a item with Image field, and a custom list derived from CollectionBase. When I add the item to the custom list, and then try to change that item Image and then get the item from the list, the Image is not set on the list item. How to make sure that the item in the list is the same as the item we created and any update will be sync between the two.I have a item with Image field, and a custom li