Markers are low quality when used with plotly

The following produces a ~20MB PNG file. However, as seen in the attached image, the marker quality appears to be quite low. Is there any way to easily improve the quality of markers?

```
import plotly.graph_objects as go
import pandas as pd
tk = '...'
fig = go.Figure()

fig.update_layout(
width=800, height=1500,
showlegend=False,
mapbox=dict(
accesstoken=tk,
center=dict(lat=32,lon=-117),
zoom=11,
style='light'
),
)

fig.add_trace(go.Scattermapbox(
lat=b['lat'], lon=b['lon'],
mode='markers',
marker=go.scattermapbox.Marker(
size=22,
color='rgb(242, 177, 172)',
opacity=0.8,
symbol=['marker']*23,
allowoverlap=True,
),
hoverinfo='none'
))

fig.show()
fig.write_image("image.png", scale=10)
```


The issue provides a Python reproduction using Plotly's Scattermapbox markers, but names no Maki asset, source file, or test. First determine which marker asset is being rendered and whether the quality problem belongs to that asset or Plotly's renderer; done requires a defined quality change and a way to validate it.

Written by the indexing model from the issue text.