1. Those images are packed up in the media folder Textures.xbt file. To change them you would need to download the svn, switch the images then rebuild the textures file.
In order to do that - you would need to extract
this into the downloaded SVN folder.
2. You would need to mod that into the skin - something like this inserted in the home.xml:
Code:
<control type="group">
<animation effect="fade" time="200" start="100" end="0">WindowClose</animation>
<control type="image">
<description>Weather image</description>
<posx>20</posx>
<posy>640</posy>
<width>40</width>
<height>40</height>
<aspectratio>keep</aspectratio>
<texture>$INFO[Weather.Conditions]</texture>
</control>
<control type="label">
<description>time label</description>
<posx>60</posx>
<posy>640</posy>
<width>200</width>
<height>40</height>
<align>left</align>
<aligny>center</aligny>
<font>fontKB</font>
<textcolor>white</textcolor>
<shadowcolor>black</shadowcolor>
<label>[b]$INFO[Weather.Temperature][/b]</label>
</control>
</control>