Images with transparency get exported without transparency

I was trying to create a texture pack for a game but the images always get exported with the transparency removed, and it only happens with these textures.
Base Texture

Hi @bricepedeflous ,

It sounds like you are experiencing a known issue with certain PNG files, unfortunately.

This can occur when the PNG file uses RGB color space, but the contents of the image have a grayscale appearance.

Do you happen to have access to Photoshop? If so, using the Gigapixel plugin via Photoshop has proven to be an adequate workaround in most situations like this.

Best,