Fixed compiler warnings

dlib/image_transforms/image_pyramid.h

@@ -1045,7 +1045,7 @@ namespace dlib
 
         long y = outer_padding;
         size_t i = 0;
-        while(y < height+outer_padding)
+        while(y < height+(long)outer_padding)
         {
             rectangle rect = translate_rect(get_rect(pyramid[i]),point(outer_padding,y));
             DLIB_ASSERT(get_rect(out_img).contains(rect));

dlib/image_transforms/interpolation.h

@@ -1306,7 +1306,8 @@ namespace dlib
         pyramid_type pyr;
         for (unsigned long i = 0; i < images.size(); ++i)
         {
-            if (images[i].size() <= max_image_size)
+            const unsigned long img_size = num_rows(images[i])*num_columns(images[i]);
+            if (img_size <= max_image_size)
             {
                 pyramid_up(images[i], temp, pyr);
                 swap(temp, images[i]);
@@ -1340,7 +1341,8 @@ namespace dlib
         pyramid_type pyr;
         for (unsigned long i = 0; i < images.size(); ++i)
         {
-            if (images[i].size() <= max_image_size)
+            const unsigned long img_size = num_rows(images[i])*num_columns(images[i]);
+            if (img_size <= max_image_size)
             {
                 pyramid_up(images[i], temp, pyr);
                 swap(temp, images[i]);
@@ -1377,7 +1379,8 @@ namespace dlib
         pyramid_type pyr;
         for (unsigned long i = 0; i < images.size(); ++i)
         {
-            if (images[i].size() <= max_image_size)
+            const unsigned long img_size = num_rows(images[i])*num_columns(images[i]);
+            if (img_size <= max_image_size)
             {
                 pyramid_up(images[i], temp, pyr);
                 swap(temp, images[i]);