diff --git a/src/backends/plotly.jl b/src/backends/plotly.jl
index 30d0c05c..474efb68 100644
--- a/src/backends/plotly.jl
+++ b/src/backends/plotly.jl
@@ -922,17 +922,7 @@ end
 # ----------------------------------------------------------------
 
 
-function _show(io::IO, ::MIME"image/png", plt::Plot{PlotlyBackend})
-    # show_png_from_html(io, plt)
-    error("png output from the plotly backend is not supported.  Please use plotlyjs instead.")
-end
-
-function _show(io::IO, ::MIME"image/svg+xml", plt::Plot{PlotlyBackend})
-    error("svg output from the plotly backend is not supported.  Please use plotlyjs instead.")
-end
-
-function Base.show(io::IO, ::MIME"text/html", plt::Plot{PlotlyBackend})
-    prepare_output(plt)
+function _show(io::IO, ::MIME"text/html", plt::Plot{PlotlyBackend})
     write(io, html_head(plt) * html_body(plt))
 end
 
diff --git a/src/backends/plotlyjs.jl b/src/backends/plotlyjs.jl
index 1bcc3845..10213214 100644
--- a/src/backends/plotlyjs.jl
+++ b/src/backends/plotlyjs.jl
@@ -1,5 +1,5 @@
 @require Revise begin
-    Revise.track(Plots, joinpath(Pkg.dir("Plots"), "src", "backends", "plotlyjs.jl")) 
+    Revise.track(Plots, joinpath(Pkg.dir("Plots"), "src", "backends", "plotlyjs.jl"))
 end
 
 # https://github.com/spencerlyon2/PlotlyJS.jl
@@ -88,8 +88,7 @@ end
 
 # ----------------------------------------------------------------
 
-function Base.show(io::IO, ::MIME"text/html", plt::Plot{PlotlyJSBackend})
-    prepare_output(plt)
+function _show(io::IO, ::MIME"text/html", plt::Plot{PlotlyJSBackend})
     if isijulia() && !_use_remote[]
         write(io, PlotlyJS.html_body(PlotlyJS.JupyterPlot(plt.o)))
     else
diff --git a/src/backends/unicodeplots.jl b/src/backends/unicodeplots.jl
index 6b4e124d..f644966d 100644
--- a/src/backends/unicodeplots.jl
+++ b/src/backends/unicodeplots.jl
@@ -212,7 +212,7 @@ end
 
 function _show(io::IO, ::MIME"text/plain", plt::Plot{UnicodePlotsBackend})
     unicodeplots_rebuild(plt)
-    map(show, plt.o)
+    foreach(x -> show(io, x), plt.o)
     nothing
 end
 
diff --git a/src/output.jl b/src/output.jl
index 6344ba9c..3a88df8c 100644
--- a/src/output.jl
+++ b/src/output.jl
@@ -168,37 +168,11 @@ const _mimeformats = Dict(
     "application/x-tex"       => "tex",
 )
 
-const _best_html_output_type = KW(
-    :pyplot => :png,
-    :unicodeplots => :txt,
-    :glvisualize => :png,
-    :plotlyjs => :html,
-    :plotly => :html
-)
-
-# a backup for html... passes to svg or png depending on the html_output_format arg
-function Base.show(io::IO, ::MIME"text/html", plt::Plot)
-    output_type = Symbol(plt.attr[:html_output_format])
-    if output_type == :auto
-        output_type = get(_best_html_output_type, backend_name(plt.backend), :svg)
-    end
-    if output_type == :png
-        # info("writing png to html output")
-        print(io, "<img src=\"data:image/png;base64,", base64encode(show, MIME("image/png"), plt), "\" />")
-    elseif output_type == :svg
-        # info("writing svg to html output")
-        show(io, MIME("image/svg+xml"), plt)
-    elseif output_type == :txt
-        show(io, MIME("text/plain"), plt)
-    else
-        error("only png or svg allowed. got: $output_type")
-    end
+# delegate mimewritable (showable on julia 0.7) to _show instead
+function Base.mimewritable(m::M, plt::P) where {M<:MIME, P<:Plot}
+    return method_exists(_show, Tuple{IO, M, P})
 end
 
-function _show(io::IO, m, plt::Plot{B}) where B
-    # Base.show_backtrace(STDOUT, backtrace())
-    warn("_show is not defined for this backend. m=", string(m))
-end
 function _display(plt::Plot)
     warn("_display is not defined for this backend.")
 end
@@ -262,6 +236,14 @@ end
 # IJulia
 # ---------------------------------------------------------
 
+const _best_IJulia_output_type = Dict(
+    PyPlotBackend       => :png,
+    UnicodePlotsBackend => :txt,
+    GLVisualizeBackend  => :png,
+    PlotlyJSBackend     => :html,
+    PlotlyBackend       => :html
+)
+
 @require IJulia begin
     if IJulia.inited
 
@@ -286,31 +268,24 @@ end
             out
         end
 
-        function IJulia.display_dict(plt::Plot)
-            output_type = Symbol(plt.attr[:html_output_format])
-            if output_type == :auto
-                output_type = get(_best_html_output_type, backend_name(plt.backend), :svg)
-            end
-            out = Dict()
-            if output_type == :png
-                mime = "image/png"
-                out[mime] = base64encode(show, MIME(mime), plt)
-            elseif output_type == :svg
-                mime = "image/svg+xml"
-                out[mime] = sprint(show, MIME(mime), plt)
-            elseif output_type == :html
-                mime = "text/html"
-                out[mime] = sprint(show, MIME(mime), plt)
-            else
-                error("Unsupported output type $output_type")
-            end
-            _extra_mime_info!(plt, out)
-            out
+        # use mimewritable to "trick" IJulia to choose the right output type
+        # Union needed to avoid method overwrite from the non-IJulia definition of mimewritable
+        AllBackends = Union{PyPlotBackend, UnicodePlotsBackend, PlotlyBackend, PlotlyJSBackend,
+            GRBackend, GLVisualizeBackend, PGFPlotsBackend, InspectDRBackend, HDF5Backend}
+        function Base.mimewritable(mime::M, plt::Plot{P}) where {M<:MIME, P<:AllBackends}
+            sym = Symbol(plt.attr[:html_output_format])
+            sym = sym === (:auto) ? get(_best_IJulia_output_type, P, :svg) : sym
+            sym === :txt  && M === MIME"text/plain"    && return invoke(mimewritable, Tuple{MIME,Plot}, mime, plt)
+            sym === :png  && M === MIME"image/png"     && return invoke(mimewritable, Tuple{MIME,Plot}, mime, plt)
+            sym === :svg  && M === MIME"image/svg+xml" && return invoke(mimewritable, Tuple{MIME,Plot}, mime, plt)
+            sym === :html && M === MIME"text/html"     && return invoke(mimewritable, Tuple{MIME,Plot}, mime, plt)
+            return false
         end
 
-        # default text/plain passes to html... handles Interact issues
-        function Base.show(io::IO, m::MIME"text/plain", plt::Plot)
-            show(io, MIME("text/html"), plt)
+        function IJulia.display_dict(plt::Plot)
+            out = invoke(IJulia.display_dict, Tuple{Any}, plt)
+            _extra_mime_info!(plt, out)
+            return out
         end
 
         ENV["MPLBACKEND"] = "Agg"