merged

ISSUE_TEMPLATE.md

@@ -12,7 +12,7 @@ If you aren't reporting a bug or problem with dlib then delete this template and
 <!-- ================================================================ -->
 
 
-<!-- Delete the above instructions and then provide a general summary of the issue in the Title above -->
+<!-- Delete the above instructions and then provide a general summary of the issue in the Title above.  Then fill out the template below. -->
 
 ## Expected Behavior
 <!--- Tell us what should happen.  What were you doing?  What part of dlib are you using?  What do you think should happen? -->

dlib/image_transforms/colormaps.h

@@ -145,7 +145,7 @@ namespace dlib
     )
     {
         typedef op_heatmap<image_type> op;
-        if (img.size() != 0)
+        if (num_columns(img) * num_rows(img) != 0)
             return matrix_op<op>(op(img,max(mat(img)),min(mat(img))));
         else
             return matrix_op<op>(op(img,0,0));
@@ -255,7 +255,7 @@ namespace dlib
     )
     {
         typedef op_jet<image_type> op;
-        if (img.size() != 0)
+        if (num_columns(img) * num_rows(img) != 0)
             return matrix_op<op>(op(img,max(mat(img)),min(mat(img))));
         else
             return matrix_op<op>(op(img,0,0));