The Display tool in SPM12 has additional function for viewing blobs, DTI images, zooming in and out, and so on.
Accessing Extended Display Options
1) Display an image using the SPM menu button;
2) Type
>>spm_orthviews('addcontext')
3) Right-click over the image
DTI Color-coded Direction Map
Locate the "evec1x/y/z" files
Right-click, and select RGB overlays, Add