diff --git a/src/args.jl b/src/args.jl
index 8c6b1f0a..82ca09d8 100644
--- a/src/args.jl
+++ b/src/args.jl
@@ -345,7 +345,7 @@ const _subplot_defaults = KW(
     :legendtitlefontcolor     => :match,
     :annotations              => [],                # annotation tuples... list of (x,y,annotation)
     :projection               => :none,             # can also be :polar or :3d
-    :aspect_ratio             => :none,             # choose from :none or :equal
+    :aspect_ratio             => :auto,             # choose from :none or :equal
     :margin                   => 1mm,
     :left_margin              => :match,
     :top_margin               => :match,
diff --git a/src/backends/gr.jl b/src/backends/gr.jl
index 8e1c833d..02aae37e 100644
--- a/src/backends/gr.jl
+++ b/src/backends/gr.jl
@@ -981,7 +981,7 @@ function gr_display(sp::Subplot{GRBackend}, w, h, viewport_canvas)
     data_lims = gr_xy_axislims(sp)
     xy_lims = data_lims
 
-    ratio = sp[:aspect_ratio]
+    ratio = get_aspect_ratio(sp)
     if ratio != :none
         if ratio == :equal
             ratio = 1
diff --git a/src/backends/pgfplots.jl b/src/backends/pgfplots.jl
index 7205b850..276ad8dd 100644
--- a/src/backends/pgfplots.jl
+++ b/src/backends/pgfplots.jl
@@ -470,7 +470,7 @@ function _update_plot_object(plt::Plot{PGFPlotsBackend})
             push!(style, string("title style = {font = ", pgf_font(sp[:titlefontsize], pgf_thickness_scaling(sp)), ", color = ", cstr, ", draw opacity = ", α, ", rotate = ", sp[:titlefontrotation], "}"))
         end
 
-        if sp[:aspect_ratio] in (1, :equal)
+        if get_aspect_ratio(sp) in (1, :equal)
             kw[:axisEqual] = "true"
         end
 
diff --git a/src/backends/plotly.jl b/src/backends/plotly.jl
index 47f03771..26a27f75 100644
--- a/src/backends/plotly.jl
+++ b/src/backends/plotly.jl
@@ -108,7 +108,7 @@ function shrink_by(lo, sz, ratio)
 end
 
 function plotly_apply_aspect_ratio(sp::Subplot, plotarea, pcts)
-    aspect_ratio = sp[:aspect_ratio]
+    aspect_ratio = get_aspect_ratio(sp)
     if aspect_ratio != :none
         if aspect_ratio == :equal
             aspect_ratio = 1.0
diff --git a/src/backends/pyplot.jl b/src/backends/pyplot.jl
index 19137b13..dc584e0d 100644
--- a/src/backends/pyplot.jl
+++ b/src/backends/pyplot.jl
@@ -1155,7 +1155,7 @@ function _before_layout_calcs(plt::Plot{PyPlotBackend})
         end
 
         # aspect ratio
-        aratio = sp[:aspect_ratio]
+        aratio = get_aspect_ratio(sp)
         if aratio != :none
             ax."set_aspect"(isa(aratio, Symbol) ? string(aratio) : aratio, anchor = "C")
         end
diff --git a/src/series.jl b/src/series.jl
index 6726de71..bba2f313 100644
--- a/src/series.jl
+++ b/src/series.jl
@@ -347,6 +347,7 @@ end
         seriestype := :heatmap
         yflip --> true
         cbar --> false
+        aspect_ratio --> :equal
         z, plotattributes[:fillcolor] = replace_image_with_heatmap(mat)
         SliceIt, m, n, Surface(z)
     end
diff --git a/src/utils.jl b/src/utils.jl
index 34099584..ef15b8b5 100644
--- a/src/utils.jl
+++ b/src/utils.jl
@@ -116,24 +116,11 @@ end
 
 function replace_image_with_heatmap(z::Array{T}) where T<:Colorant
     n, m = size(z)
-    # idx = 0
     colors = ColorGradient(vec(z))
     newz = reshape(range(0, stop=1, length=n*m), n, m)
     newz, colors
-    # newz = zeros(n, m)
-    # for i=1:n, j=1:m
-    #     push!(colors, T(z[i,j]...))
-    #     newz[i,j] = idx / (n*m-1)
-    #     idx += 1
-    # end
-    # newz, ColorGradient(colors)
 end
 
-function imageHack(plotattributes::AKW)
-    is_seriestype_supported(:heatmap) || error("Neither :image or :heatmap are supported!")
-    plotattributes[:seriestype] = :heatmap
-    plotattributes[:z], plotattributes[:fillcolor] = replace_image_with_heatmap(plotattributes[:z].surf)
-end
 # ---------------------------------------------------------------
 
 "Build line segments for plotting"
@@ -710,6 +697,19 @@ function has_attribute_segments(series::Series)
     return any((typeof(series[attr]) <: AbstractVector && length(series[attr]) > 1) for attr in [:seriescolor, :seriesalpha, :linecolor, :linealpha, :linewidth, :linestyle, :fillcolor, :fillalpha, :markercolor, :markeralpha, :markerstrokecolor, :markerstrokealpha]) || any(typeof(series[attr]) <: AbstractArray for attr in (:line_z, :fill_z, :marker_z))
 end
 
+function get_aspect_ratio(sp)
+    aspect_ratio = sp[:aspect_ratio]
+    if aspect_ratio == :auto
+        aspect_ratio = :none
+        for series in series_list(sp)
+            if series[:seriestype] == :image
+                aspect_ratio = :equal
+            end
+        end
+    end
+    return aspect_ratio
+end
+
 # ---------------------------------------------------------------
 
 makekw(; kw...) = KW(kw)