Plz point error in query

Hi all

following is my query

select
pd.PropId as PropId,
pd.LocId as LocId,pd.PropNature as [PropNature],
lm.LocationName as LocationName,lm.Latitude as [Latitude],lm.Longitude as [Longitude],
CASE WHEN pd.Shop=1 THEN 'Shop ' else '' END +
CASE WHEN pd.Office=1 THEN 'Office ' else '' END +
CASE WHEN pd.ATM=1 THEN 'ATM ' else '' END +
CASE WHEN pd.Godown=1 THEN 'Godown ' else '' END +
CASE WHEN pd.Basement=1 THEN 'BMT ' else '' END +
CASE WHEN pd.Hall=1 THEN 'Hall ' else '' END +
CASE WHEN pd.Cabin=1 THEN 'Cabin ' else '' END +
CASE WHEN pd.Floor=1 THEN 'Floor ' else '' END +
CASE WHEN pd.ShowRoom=1 THEN 'Showroom ' else '' END +
CASE WHEN pd.Ind_House=1 THEN 'Ind. House ' else '' END +
CASE WHEN pd.Flat_Apartment=1 and DevId>0 THEN 'Builder Flat ' else '' END +
CASE WHEN pd.Flat_Apartment=1 and DevId=0 THEN 'Flat/Apartment ' else '' END as PropType,
Pd.NoOfFloor as [NoOfFloors],
case when FL_BMT=1 then 'BMT ' else '' end +
case when FL_GF=1 then 'GF ' else '' end +
case when FL_1F=1 then '1F ' else '' end +
case when FL_Mezz=1 then 'MZN ' else '' end +
case when FL_2F=1 then '2F ' else '' end +
case when FL_3F=1 then '3F ' else '' end +
case when FL_4F=1 then '4F ' else '' end +
case when FL_5F=1 then '5F ' else '' end +
case when FL_TRR=1 then 'TRR ' else '' end as [Floors],
convert(varchar(50),pd.Total_Area) + '' + pd.postfix as [TotalArea],
pd.Address_Visible as [Address],
pd.PropFor as PropFor,
convert(varchar(50),pd.Budget) + ' ' + pd.BudgetPostFix as [Budget],
pd.Bedroom as [Bedroom],bm.BrCaption as BrCaption,
(if not exists(select ImgUrl from PropertyImages where PropId=31)
begin
(select top(1) 'notavailable.jpg' as ImgUrl from PropertyImages)
end
else
begin
(select Imgurl as ImgUrl from PropertyImages where PropId=31)
end ) as ImgUrl
from
PropertyDetails as pd
left outer join LocationMaster as lm on pd.LocId=lm.LocID
left outer join BedroomMaster as bm on pd.Bedroom=bm.BrID
where pd.Flag=1 and pd.PropId=31

following is my error
Msg 156, Level 15, State 1, Line 32
Incorrect syntax near the keyword 'if'.
Msg 102, Level 15, State 1, Line 39
Incorrect syntax near ')'.



Plz Point error in above query
Provided i am using above query in writing stored procedure so that to check i am providing propId=31 for check and "notavailableImg" is in table
thx

Sushat