overlay.png creation with Photoshop

[puhl]

I want to use print overlays in a few of my photo booth layouts. Therefore I am investigating.... and reading chapter 9.14 of the manual and several forum threads.

Chapter 9.14 states that PNG images for overlays should be saved as 24-bit color images with an 8-bit alpha channel used for the transparency information.

Several questions:
1. How is this accomplished with Photoshop CC? -- Just by saving the PSD object as PNG file? Do other options need to be selected as well. My PSD object has RGB and 8 bit, a layer mask with transparency information, and that layer mask is also an alpha channel.
2. How can I check if a PNG file follows the above spec?
3. Is there any pro/con whether dropshadows for the photos on the printout are generated by adding them to the background.jpg or creating an overlay.png for them?

Thanks
Peter

[Chris Breeze]

Saving a PSD file as a PNG file should work provided it is a 24 bit image (i.e. contains color).

It's probably simpler to use a background.jpg image for drop shadows. OTOH using a semi-transparent shadow in a PNG overlay might be easier to reuse in other layouts because it could be added to any background.