The principle reason for installing MakeSpot is to set or modify the color selection that's available in Agendus. Your allowed 7 colors and these can be set in MakeSpot and then Agendus will reflect the changes that you've selected provided you save the set.
Also, you can select multiple days easier in MakeSpot that will show up in Agendus. These multiple days can either be individually selected or you can also have MakeSpot do Holidays in a global mode.
To the best of my knowledge the Photo app is strictly their for conversion of "off" types so that you can use it in Agendus for wallpaper. But I haven't installed it.
MakeSpot is on my Treo though.
EDIT: Paul - don't bother looking for the MakeSpot instructions in the Agendus manual.....their is not an English Manual for MakeSpot. It's pretty simple to figure out so you won't have any problem. 
