Thought this was a good place to add a blingee update to this about the white background showing up i.e.:
Look at the squares behind the stamp a dark grey means the background will not show up, the lighter the grey the more likely it will have at least a white background behind it causing a square shape rather than the outline of the image.
However blingee have found a sort of solution to this and if a stamp, where the white background shows up, is now used with a picture that has a white background it is merged together so that the white background now matches in. However it does mean that transparent/translucent i.e. white flowers will no longer show up.