The tutorial shows an older version in which you're able to include empty slots on an exported sheet, has this been removed? Right now I have a 8x2 grid but only 8 frames, I want all the bottom ones to be empty. Is there any way to do this in the new version? 

Hi there!

If you cut up the sprite sheet inside the program which included cutting up the transparent frames, you can include them in the sprite sheet.

However if you imported the 8 frames as separate images and then want to add 8 transparent frames it is currently not possible.

Hi,

I added an old version to the downloadable package   that has the feature you want! 

https://lion-in-a-box-games.itch.io/spritesheet-mp4-gif-converter-pro/devlog/851550/v311-included-old-version-301-to-allow-for-transparent-sprite-sheet-areas

Install the G.A.S. Old version 3.0.1 from the package, and then  you proceed:

1. Import the 8 frames into G.A.S.
2. Make sure "auto-adjust to include all frames" is unselected
3. Set the horizontal and vertical frames to 8 and 2
4. Set the last frame to 16
5. Now export as "Single Image" to get the sprite sheet with the empty area you need

The only feature missing in this old version is the "Manual Crop" FX function. If you don't need this function this might be a good temporary solution for you before I drop the next big update that will also include empty sprites feature.

Have fun with it!