fix pivot png
fix pivot png

jakirkham/bokeh,timsnyder/bokeh,bokeh/bokeh,stonebig/bokeh,ericmjl/bokeh,bokeh/bokeh,stonebig/bokeh,bokeh/bokeh,timsnyder/bokeh,dennisobrien/bokeh,bokeh/bokeh,bokeh/bokeh,ericmjl/bokeh,dennisobrien/bokeh,mindriot101/bokeh,ericmjl/bokeh,dennisobrien/bokeh,mindriot101/bokeh,jakirkham/bokeh,timsnyder/bokeh,timsnyder/bokeh,ericmjl/bokeh,jakirkham/bokeh,mindriot101/bokeh,jakirkham/bokeh,mindriot101/bokeh,dennisobrien/bokeh,ericmjl/bokeh,stonebig/bokeh,stonebig/bokeh,jakirkham/bokeh,timsnyder/bokeh,dennisobrien/bokeh