open up photoshop and then the picture you would like to make flash. go to image > adjustments > black & white. mess with all the slider bars until your picture looks best.

make a new layout (layers menu > new > layer). choose the color you want it to flash to and fill in the layer using the paint bucket tool. change the layer style to "overlay". merge the layers (layers > flatten image). select all (ctrll+a), copy the image, and paste it in animation shop 3 (ctrl+v)
go back to photoshop. go to the history window and undo the flatten image. change the color layer to the other color you want it to flash. repeat the flatten image step and paste that into animation shop 3 (ctrl+shift+l) or (edit > paste > after current frame)

file > save to save the image.
















