Issue: 🐛Bug report | FBS Image warp for 2D images returns blank images

[stevenlabelle]

Description: Using the Image Warp tool with 2D images generates a blank image. Removing the filter does not reset the image.
Version: Dev version 2.7.0.5625a215a

To reproduce:

1. Load a completed model (e.g., from FEBioWarp, test1_v4.xplt).
2. Load a raw template image (template.raw for test1_v4.xplt). The image can be viewed with the image viewer.
3. Advance to a non-zero timestep and apply the Image Warp function.
4. The resulting image is blank.

Notes: The image warp tool behaved as expected when a 2-slice thick 3D image was generated by duplicating the 2D image in the Z direction.