I've had a number of comments about backscenes/backdrops I used for my photos (and on the back of my gaming table).
On the photo backdrop I used :
PECO SK-32 Country Landscape - MEDIUM 178mm x 559mm (7in x 22in)
I've also used for my gaming table:
PECO SK-19 Sky Background (clouds) - LARGE 228mm x 736mm (9in x 29in)
PECO SK-28 Sky Background (Clear) - LARGE 228mm x 736mm (9in x 29in)
There are a number of others available from Busch, Vollmer and Faller which may be useful too. A nice one is the Busch CountrySide (BU 2872), this is 198x34cm in size though, link to imagehttp://www.eurorailhobbies.com/ERH/eurorailhobbiesdetail.asp?pageid=&MN=12&stock=BU-2872
PECO is a UK model railway supplier. It may be you have to search on the Internet for a stockist which will supply them in your country. If the following link works you can see the range I usually select from,
http://www.gaugemaster.co.uk/search_results.asp?searchstring=%ACoo%AC+scenics+backscene&style=main&andor=View&method=kws&searchtitle=Backscenes&strType=OO&ob=p_d¤tpage=1 (GaugeMaster do ship overseas).
Hope you've found this info useful