regarding the windows mobile development

hi ,
i ave been in developing a game for windows mobile 5.0 smartphone ..
i am using visual studio 2005 to develop the application .
i have used Image Attribute class for setting transparency by
following method.
my application is having the following problems:
1. i am using double buffering concept , the application is slow
while handling keypress . what s the method to make it fast .
2. in windows mobile 5.0 emulator , the white color in the images had
become transparent .
3. . i am using more than 11 .png images , around 74 kb size .
when i open the the .exe file inside the bin folder , the .exe file is
showing outof memory exception . but the build is running well in all
the emulators .
could any one help me in solving the above issues .