VBA differentiate between image with transparency vs. solid fill

Question

On my slides I have images (all are PNGs) that are either a square/rectangle of solid image, or have transparency - for reference think of rectangle vs star.

I wrote a macro which adds a black 3pt border to all images, however I'd like the images with transparency to have a shadow instead of a border - while solid images keep the black border.

I've attached an image to illustrate exactly what I mean. http://i.stack.imgur.com/hs4ma.png

Thank you in advance! :)

Answer 1

As far as I know, there's nothing in the OM that tells you whether an image has an alpha channel (ie, a transparent PNG) or not.

You'd need to get access to the image itself and work out a way of examining it, for example using FreeImage.

Not a simple task.