You only uploaded a .img file - a .hdr file with the header is required to interpret the image file (e.g. NIfTI data can be stored as a single .nii file or a pair of files .hdr/.img). 

You can create nice figures with NIfTI files using MRIcroGL
  https://www.nitrc.org/plugins/mwiki/index.php/mricrogl:MainPage#Loading_Overlays
You can also load the NIfTI image as an overlay on a mesh, but you will want to make sure the voxel based image has the same shape as the mesh:
  https://www.nitrc.org/plugins/mwiki/index.php/surfice:MainPage#Scripting_a_painted_overlay