Bug fix when generating thumbnails for 4D images
Bug fix when generating thumbnails for 4D images

NicolasSchnitzler/medInria-public,rdebroiz/medInria-public,aabadie/medInria-public,aabadie/medInria-public,rdebroiz/medInria-public,NicolasSchnitzler/medInria-public,NicolasSchnitzler/medInria-public,rdebroiz/medInria-public,aabadie/medInria-public