Millis If the image size changes after deleting the blank space, you will need to fix the UVs of the mesh. For more information, please see the user guide: 网格附件 - 调整图片大小
However, as Spinebot's answer mentions, it is possible to work on images with large blank spaces while working in the Spine editor, and then remove the whitespace at once when doing texture packing. To do this, either enable Strip whitespace X/Y in the texture packer settings, or use Polygon packing:
