From halowresource:
<LayoutElement Type="Text" Font="statusfont">
...
<Timer Type="delay">0000</Timer>
<Timer Type="cycleon">3000</Timer>
<Timer Type="cycleoff">9000</Timer>
</LayoutElement>
<LayoutElement Type="Text" Font="statusfont">
...
<Timer Type="delay">3000</Timer>
<Timer Type="cycleon">3000</Timer>
<Timer Type="cycleoff">9000</Timer>
</LayoutElement>
<LayoutElement Type="Text" Font="statusfont">
...
<Timer Type="delay">6000</Timer>
<Timer Type="cycleon">3000</Timer>
<Timer Type="cycleoff">9000</Timer>
</LayoutElement>
<LayoutElement Type="Text" Font="statusfont">
...
<Timer Type="delay">9000</Timer>
<Timer Type="cycleon">3000</Timer>
<Timer Type="cycleoff">9000</Timer>
</LayoutElement>
Cycleon is how long each pic appears for, and cycleoff is how long each pic is invisible for
You want cycleon to be 20000 ms for each pic
Cycleoff is a bit more complicated:
Total time = 20000 * 8 = 160000
Subtract the cycleon time from that
160000 - 20000 = 140000 (CycleOff)
Therefore each pic should be visible for 20 seconds and invisible for 140 seconds
Delay is how long each pic takes to appear for the first time
pic1 delay = 0 ms
pic2 delay = 20000 ms
pic3 delay = 40000 ms
pic4 delay = 60000 ms
etc
As for the bounce, put on a bounce modifier for each pic, with bouds: left=10, right=630, top=10, bottom=470
(10 pixels away from each edge)