iOS Question KeyValueStore save a map with different types

hi,

I have a map with different type (custom types, text, bitmaps,...)
I am trying to save this map with KVS to be able to send it to another user.
But KVS return an error "Can not serialize UIImage..."

thus a question.
How can I save this map to file or input bytes to be able to send it with HttpUtils.
Is there maybe a way to archive a map? and it will be converted to bytes.
regards