Avoid duplication of photos on the same album (googlecl picasa upload)

[GoogleCodeExporter]

===NOTE===
If you're asking for a new service that isn't supported by gdata-python-
client, this will immediately get flagged as WontFix.
==========

What service (Calendar, Docs, Picasa) should be enhanced?
Picasa

What is the enhancement?
Avoid re-uploading the same photos to the same album, this will produce 
duplicates. The default behavior should be to not upload photos already in the 
album. An option could be added to modify this default and allow the creation 
of duplicates. 

Original issue reported on code.google.com by brunolu...@gmail.com on 20 Nov 2011 at 8:58

[GoogleCodeExporter]

IMHO, it should be left as is by default, with a --replace option added that 
does an optional 'get', check and 'delete' if required.

Googlecl is primarily useful for further scripting, rather than literally 
typing the commands on the cli. Doing a replace using the gdata-python library 
requires a 'get' to find existing photo, a 'delete' to delete it if it exists, 
and finally a 'post' to put up the new version. And doing a 'get' per-photo to 
check whether to for a replace by default is inefficient, especially when many 
scripts will be batch processing.

In my own batch upload scripts, I do a 'get' on the album to retrieve the 
photo's that are currently there, then check (and remove) against those I'm 
uploading. This is far more efficient than doing a 'get' on each photo.

Original comment by moro...@gmail.com on 1 Apr 2012 at 12:45