I discovered that I has to URL encode the link to icon. So this sorted it out
user_icon = URI.encode(facebook_profile_picture(user_id))
provider1_icon =URI.encode("http://graph.facebook.com/100006411879480/picture?type=square")
....
return URI.encode("http://maps.google.com/maps/api/staticmap?center=#{customer}&zoom=9&size=#{width}x#{height}&scale=2&sensor=false&markers=color:0xEE82EE|#{customer}&markers=icon:#{user_icon}|#{provider0}&markers=color:0x00BFFF|#{provider1}&markers=icon:#{provider1_icon}|#{provider2}")
end