In Plotly, place an image of any size at any position on the X axis in datetime format.

plotly_place_image_on_datetime_xaxis.py

import plotly.graph_objects as go
from datetime import datetime, timedelta

# Create figure
fig = go.Figure()

now = datetime.now()
print(now)

# Increment 1 hour
x = [(now + timedelta(hours=i)) for i in range(5)]

# Add trace
fig.add_trace(
    go.Scatter(x=x, y=[1.23, 2.5, 0.0, 3, 1, 2])
)

# msec based
hour_width_on_timestamp = 1000*3600

# Add images
fig.add_layout_image(
        dict(
            source="https://images.plot.ly/language-icons/api-home/python-logo.png",
            xref="x",
            yref="y",
            x=now, # Image position x is datetime
            y=1,
            # Sizes are selected smaller one if hold aspect ratio
            sizex=hour_width_on_timestamp, # sizex is must be integer or float format
                                           # the format is msec based
            sizey=2,
            opacity=0.7,
            # sizing="stretch", # Comment out if want to hold aspect ratio
            layer="above" # above or below
        )
)

# Set templates
fig.update_layout(template="plotly_white")

fig.show()