diff --git a/models/openface/nn2.def.lua b/models/openface/nn2.def.lua
index 2000246..11d64fc 100644
--- a/models/openface/nn2.def.lua
+++ b/models/openface/nn2.def.lua
@@ -22,6 +22,8 @@
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
 
+imgDim = 224
+
 function createModel()
    local net = nn.Sequential()
 
diff --git a/models/openface/nn4.def.lua b/models/openface/nn4.def.lua
index 35d4a7f..66a790a 100644
--- a/models/openface/nn4.def.lua
+++ b/models/openface/nn4.def.lua
@@ -22,6 +22,8 @@
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
 
+imgDim = 96
+
 function createModel()
    local net = nn.Sequential()
 
diff --git a/training/donkey.lua b/training/donkey.lua
index 05a1e8c..e9bace3 100644
--- a/training/donkey.lua
+++ b/training/donkey.lua
@@ -25,8 +25,8 @@ if not os.execute('cd ' .. opt.data) then
     error(("could not chdir to '%s'"):format(opt.data))
 end
 
-local loadSize   = {3, opt.imgDim, opt.imgDim}
-local sampleSize = {3, opt.imgDim, opt.imgDim}
+local loadSize   = {3, imgDim, imgDim}
+local sampleSize = {3, imgDim, imgDim}
 
 -- function to load the image, jitter it appropriately (random crops etc.)
 local trainHook = function(self, path)
diff --git a/training/opts.lua b/training/opts.lua
index 109e2de..d0b7888 100644
--- a/training/opts.lua
+++ b/training/opts.lua
@@ -45,7 +45,7 @@ function M.parse(arg)
    ---------- Model options ----------------------------------
    cmd:option('-retrain', 'none', 'provide path to model to retrain with')
    cmd:option('-modelDef', '../models/openface/nn4.def.lua', 'path to model definiton')
-   cmd:option('-imgDim', 96, 'Image dimension. nn2=224, nn4=96')
+   -- cmd:option('-imgDim', 96, 'Image dimension. nn2=224, nn4=96') Provided by model def.
    cmd:option('-embSize', 128, 'size of embedding from model')
    cmd:option('-alpha', 0.2, 'margin in TripletLoss')
    cmd:text()