edited image not being saved and displayed properly

[SUBSCRIBE MAPSERVER-USERS mapuser]

hi, i have set the EXTENT to the extent of particular postcode. i think 
you are right that the extent changes every time when i click, which is 
not in the 

specified extent. 

how can i set the extent values. i want to show that particular area. if i 
set the extent value to the extent of my table, then how can i be able 
to show the 

small area.

my layer status is set to ON
and projection is 27700
units is meters

my mapfile is

MAP
  NAME           EX1.9_
  IMAGETYPE      PNG24
  UNITS METERS
  EXTENT 248029.59375 54095.69921875 248179.609375 
54245.703125# EXTENT OF SPECIFIC AREA

  SIZE           400 300
  #SHAPEPATH      "../data"
  SYMBOLSET      "../symbols/symbols35.sym"
  FONTSET        "../fonts/fonts.list"

 WEB
    TEMPLATE  'example1-9.html'
    IMAGEPATH '/ms4w/tmp/ms_tmp/'
    IMAGEURL  '/ms_tmp/'
  END

  PROJECTION
"proj=tmerc"
"lat_0=49"
"lon_0=-2"
"k=0.999601"
"x_0=400000" 
"y_0=-100000"
"ellps=airy"
"units=m"
"no_defs "
END #end projection

# Start of LAYER DEFINITIONS ---------------------------------------------
LAYER # States polygon layer begins here
    NAME         tarea
    CONNECTIONTYPE postgis
    CONNECTION "user=postgres password=postgres 
dbname=MasterMap host=localhost port=5432"

    DATA "geom from topographicarea"
    TYPE POLYGON
    STATUS       ON
PROJECTION
"proj=tmerc"
"lat_0=49"
"lon_0=-2"
"k=0.999601"
"x_0=400000" 
"y_0=-100000"
"ellps=airy"
"units=m"
"no_defs "
END #end projection

CLASS
NAME "buildings"
TYPE POLYGON
STATUS ON
EXPRESSION ('[theme]'='Buildings')
STYLE
                  
			COLOR  255 196 196
			OUTLINECOLOR 0 0 0
END
END #my class end
END #LAYER
END #END MAP