Overlaying two Images with good quality.

Hello, I work in experimental physics, doing Imaging experiments now. I acquired two Images, 1. is Image of cell and 2.is fluorescent dots(few fluorescent spots). I would like to overlay fluorescent dots image on to the cell Image. I used the "AlphaData" command but the cell Image is not that clear. I would like to see clear cell Image with fluorescent dots on it by making transparent background of fluorescent dots image (as they are very few dots). My Image size is 16bit (480x640).

Thank You,

[Walter Roberson]

Please post some sample images.