diff --git a/core/formats/png.cpp b/core/formats/png.cpp
index 54e74c42e7..7aa972e96d 100644
--- a/core/formats/png.cpp
+++ b/core/formats/png.cpp
@@ -70,16 +70,16 @@ namespace MR
       }
 
       H.size(0) = png.get_width();
-      H.stride(0) = -3;
+      H.stride(0) = -2;
 
       H.size(1) = png.get_height();
-      H.stride(1) = -4;
+      H.stride(1) = -3;
 
       H.size(2) = 1;
-      H.stride(2) = 1;
+      H.stride(2) = 4;
 
       if (H.ndim() == 4)
-        H.stride(3) = 2;
+        H.stride(3) = 1;
 
       H.spacing (0) = H.spacing (1) = H.spacing (2) = 1.0;
       H.transform().setIdentity();
diff --git a/core/header.cpp b/core/header.cpp
index ad5b49acf8..48240f20af 100644
--- a/core/header.cpp
+++ b/core/header.cpp
@@ -785,12 +785,13 @@ namespace MR
     Header result (headers[0]);
 
     if (axis_to_concat >= result.ndim()) {
+      Stride::symbolise (result);
       result.ndim() = axis_to_concat + 1;
       result.size(axis_to_concat) = 1;
+      result.stride(axis_to_concat) = axis_to_concat+1;
+      Stride::actualise (result);
     }
 
-    result.stride (axis_to_concat) = result.ndim()+1;
-
     for (size_t axis = 0; axis != result.ndim(); ++axis) {
       if (axis != axis_to_concat && result.size (axis) <= 1) {
         for (const auto& H : headers) {
diff --git a/testing/binaries/data b/testing/binaries/data
index 68869a7fe0..f65db971d0 160000
--- a/testing/binaries/data
+++ b/testing/binaries/data
@@ -1 +1 @@
-Subproject commit 68869a7fe0780c7b1e9577ba68466d5b407a3fe8
+Subproject commit f65db971d019675874751c2111877531e8bb5544
diff --git a/testing/binaries/tests/mrconvert b/testing/binaries/tests/mrconvert
index 4b9460dcce..e012f18e92 100644
--- a/testing/binaries/tests/mrconvert
+++ b/testing/binaries/tests/mrconvert
@@ -8,8 +8,8 @@ mrconvert mrconvert/in.mif tmp.nii  && testing_diff_image tmp.nii mrconvert/in.m
 mrconvert mrconvert/in.mif -datatype float32 tmp.nii.gz -force && testing_diff_image tmp.nii.gz mrconvert/in.mif
 mrconvert mrconvert/in.mif -strides 3,2,1 tmp.mgh  && testing_diff_image tmp.mgh mrconvert/in.mif
 mrconvert mrconvert/in.mif -strides 1,3,2 -datatype int16 tmp.mgz  && testing_diff_image tmp.mgz mrconvert/in.mif
-mrconvert mrconvert/in.mif tmp-[].png && echo -e "1 0 0 0\n0 1 0 0\n0 0 1 0\n" > tmp.txt && testing_diff_image tmp-[].png $(mrcalc mrconvert/in.mif 0 -max - | mrtransform - -replace tmp.txt -)
-mrconvert unit_warp.mif tmp-[].png -datatype uint8 -force  && echo -e "1 0 0 0\n0 1 0 0\n0 0 1 0\n" > tmp.txt  && testing_diff_image tmp-[].png $(mrcalc unit_warp.mif 0 -max -round - | mrtransform - -replace tmp.txt - | mrconvert - -vox 1,1,1 -)
+rm -f tmp-*.png && mrconvert mrconvert/in.mif tmp-[].png && testing_diff_image tmp-[].png $(mrcalc mrconvert/in.mif 0 -max - | mrtransform - -replace identity.txt -)
+rm -f tmp-*.png && mrconvert unit_warp.mif tmp-[].png -datatype uint8 && testing_diff_image tmp-[].png $(mrcalc unit_warp.mif 0 -max -round - | mrtransform - -replace identity.txt - | mrconvert - -vox 1,1,1 -)
 mrconvert dwi.mif tmp-[].mif -force && testing_diff_image dwi.mif tmp-[].mif
 mrconvert dwi.mif -coord 3 0:2:end tmp1.mif -force && mrconvert tmp-[0:2:66].mif tmp2.mif && testing_diff_header -keyval tmp1.mif tmp2.mif && testing_diff_image tmp1.mif tmp2.mif
 mrconvert mrcat/voxel[].mih - | testing_diff_header -keyval - mrcat/all_axis0.mif
@@ -17,8 +17,13 @@ mrconvert mrcat/all_axis3.mif tmp-[].mif -force && testing_diff_header -keyval t
 mrconvert dwi.mif tmp-[]-[].mif -force && testing_diff_image dwi.mif tmp-[]-[].mif
 mrconvert dwi.mif -coord 3 1:2:end -axes 0:2,-1,3 - | testing_diff_image - mrconvert/dwi_select_axes.mif
 mrinfo template.mif.gz -transform > tmp.txt && mrconvert template.mif.gz tmp[].png -force && mrconvert tmp[].png -vox 2.5 - | mrtransform - -replace tmp.txt - | mrcalc - 255 -div - | testing_diff_image - $(mrcalc template.mif.gz 1.0 -min -) -abs 0.002
-rm -f tmpaxial*.png && mrconvert template.mif.gz -coord 2 9,19,29,39,49 tmpaxial[].png && testing_diff_image tmpaxial[].png mrconvert/axial[].png
-rm -f tmpcoronal*.png && mrconvert template.mif.gz -coord 1 17,32,47,62,77 -axes 0,2,1 tmpcoronal[].png && testing_diff_image tmpcoronal[].png mrconvert/coronal[].png
-rm -f tmpsagittal*.png && mrconvert template.mif.gz -coord 0 27,47,67 -axes 1,2,0 tmpsagittal[].png && testing_diff_image tmpsagittal[].png mrconvert/sagittal[].png
-rm -f tmpmask*.png && mrconvert mask.mif tmpmask[].png && testing_diff_image tmpmask[].png mrconvert/mask[].png
-rm -f tmptissues*.png && mrconvert dwi2fod/msmt/tissues.mif tmptissues[].png && testing_diff_image tmptissues[].png mrconvert/tissues[].png
+rm -f tmpaxial*.png && mrconvert template.mif.gz -coord 2 9,19,29,39,49 tmpaxial[].png && testing_diff_image tmpaxial[].png mrconvert/pngaxial[].png
+mrconvert mrconvert/pngaxial[].png - | testing_diff_image - mrconvert/pngaxial.mif.gz
+rm -f tmpcoronal*.png && mrconvert template.mif.gz -coord 1 17,32,47,62,77 -axes 0,2,1 tmpcoronal[].png && testing_diff_image tmpcoronal[].png mrconvert/pngcoronal[].png
+mrconvert mrconvert/pngcoronal[].png - | testing_diff_image - $(mrconvert mrconvert/pngcoronal.mif.gz -axes 0,2,1 -)
+rm -f tmpsagittal*.png && mrconvert template.mif.gz -coord 0 27,47,67 -axes 1,2,0 tmpsagittal[].png && testing_diff_image tmpsagittal[].png mrconvert/pngsagittal[].png
+mrconvert mrconvert/pngsagittal[].png - | testing_diff_image - $(mrconvert mrconvert/pngsagittal.mif.gz -axes 1,2,0 -)
+rm -f tmpmask*.png && mrconvert mask.mif tmpmask[].png && testing_diff_image tmpmask[].png mrconvert/pngmask[].png
+mrconvert mrconvert/pngmask[].png - | testing_diff_image - mrconvert/pngmask.mif.gz
+rm -f tmptissues*.png && mrconvert dwi2fod/msmt/tissues.mif tmprgb[].png && testing_diff_image tmprgb[].png mrconvert/pngrgb[].png
+mrconvert mrconvert/pngrgb[].png - | testing_diff_image - $(mrconvert dwi2fod/msmt/tissues.mif -vox 1,1,1 - | mrtransform - -replace identity.txt - | mrcalc - 255 -mult -round 255 -min -)