There are two different icons, a ‘current condition icon’ and a ‘forecast icon’. The former (current condition icon) is controlled by several setup screens, since it’s source may be selected to be from a nearby METAR, your weather station (rain/no rain), and/or a solar sensor (for cloud conditions based on insolation).
The summary image is what you see if you click on the WD main display where the picture is (just above the area showing the time, data received and data quality). It will pop open three windows, one is the Summary Image, one is the Metar (if metar enabled), and one is the forecast (if NOAA forecast downloads are enabled).
The Carterlake/AJAX templates don’t use the ‘summary image’ nor the ‘forecast icon’ directly – they use the icon number for the current condition to display a small icon which should represent the current weather condition.
To set up the icon with a solar sensor, I recommend you use the Control Panel, Solar Sensor Setup, Thresholds/Icon/Solar Description TAB
Tick all 5 check boxes in the ‘Icon from solar/solar sensor’,
If your solar sensor is obscured by surrounding trees or hills, then enable the fine-tune times to reflect when to ignore the solar sensor with minutes after local sunrise and minutes before local sunset.
Then select the Max Solar Time of Day/Time Zone/Lat/Long TAB and tick 'Update the solar value from this max reading…;, and set the Latitude/Longitude, timezone values and turn the main switch to ON and hit OK to save the settings.
Then in Control Panel, Summary Images & Icons, Main Screen icon/Forecast icon Setup/Text Scroll TAB,
Tick ‘Use Downloaded Metar to update the Icon’, ‘Include extra weather conditions from downloaded Metar’, Show the Metar image on the web page’, and ‘Your stations rain/wind/fog overrides the metar’. and hit OK to save the setting.
This assumes you’ve got a nearby METAR setup to pull (using the Control Panel, FTP &Connections Metar…, Metar Download TAB, then have ticked the ‘Use the metar to update WD’s main weather condition report’ in addition to having a metar specified for download.
With all that, what should happen is the Solar sensor will rule during the day for cloud conditions based on percentage of solar v.s. expected max for time/lat/longitude. It will be replaced with ‘rain/light rain/stopped raining’ based on your rain gauge. Then at night, the icon will be set based on what the nearby metar has to say about cloud conditions, with your station’s rain status overriding.