i use MFC and DX9 to implement it. i split the main window,the left view to choose the pic and display it's preview. the right view to display the map. and i want to ask whether i have to init the library twice ,because in the left view i will render the pic for preview and in the right view i will render the pic too.

No, you should be fine, if I understand you correctly. Attempting to init DX9 twice (via multiple calls to Direct3DCreate9 will probably get you the same COM pointer, underneath (don't quote me on that though, I don't have the documentation handy or the means to test it right now).

What you'll want to look into is multiple viewports or (even better) multiple swap chains. There's a code sample (not exactly a tutorial, but easy enough to follow) for both here and if you search a bit using those terms, you can probably find others.

Thank u very much!
i download the samplers, i think it's what i wanted to get !