Can Bulk Mockup generate PNG files with transparent backgrounds?

Yes, Bulk Mockup can generate PNG files with transparent backgrounds, but it depends on a few factors:

1. Template File Format: The original mockup file (usually a PSD) must have a transparent background or allow for one. If the background is baked into the design, transparency won't be possible.
2. Export Settings: You need to configure Bulk Mockup to export in PNG format with transparency enabled. Make sure you're not flattening layers that would remove transparency.
3. Layer Visibility: Ensure that any background layers in your mockup are hidden or transparent before exporting.
4. File Format: The file & designs should be in RGB format for it to export transparent images
5. Export: You should set the export format to png
   

If set up correctly, Bulk Mockup should be able to output transparent PNGs.