You can modify the HTML as needed but the a basic example looks like this:
datadict = dict(x = [1,5],
y = [4,10],
img = ['https://raw.githubusercontent.com/holoviz/panel/master/doc/_static/logo_horizontal.png',
'https://raw.githubusercontent.com/holoviz/panel/master/doc/_static/logo_stacked.png'])
hover = HoverTool(tooltips="""
<div>
<div>
<img src="@img" width=100 style="float: left; margin: 0px 15px 15px 0px; border="2"></img>
<div>
<span style="font-size: 15px;">Location</span>
<span style="font-size: 10px; color: #696;">(@x, @y)</span>
</div>
</div>
""")
df_test =pd.DataFrame.from_dict(datadict)
df_test.hvplot.scatter(x='x',y='y', hover_cols=['img'], tools=[hover])
