If you wish to use a custom image file as a material, please follow these steps.
1. Select the Item Right Click Change Material Current Selection
2. You will then see a window as shown below. Click Replace.
3. Click on Manage Materials and then select Add (This Design) or Add (Any Design) in the 'Manage Material' dialog window.
[Note: 'Add (This Design)' will add the image file as a material option only to the current design, while 'Add (Any Design)' will add the image file as material option to all designs]
4. Select the image file you wish to use as a material and click Open.
5. You will then see the image file added to the 'Manage Materials' dialog window. Click OK to continue.
6. Select My Images from the drop-down menu in the 'Select Material' window as shown below. You will see the image you have added. Select the image you want to use as a material and click OK.
7. Click OK to confirm material change.
8. This will change the material of the selected unit to the image you have selected to use as a material.