I understood, that the original PNG image is 300x150 pixel large and you want it to be stored as two 150x150 pixel large frames, is it right?
In such case:
1.) Create a bitmap with two frames and framesize 150x150:
XBitmap* bitmap = EwCreateBitmap( EW_PIXEL_FORMAT_NATIVE, EwNewPoint( 150, 150 ), 0, 2 )
2.) When you decompress the PNG file, you have to treat the both frames individually.
You lock the first bitmap frame and copy there the (left?) 150x150 pixel large area from the source PNG file. Then you lock the second frame and copy there the remaining (right?) part of the original PNG file.
To lock the first frame you call the function EwLockBitmap( bitmap, 0, EwNewRect( 0, 0, 150, 150 ), 0, 1 ).
To lock the second frame you call the function EwLockBitmap( bitmap, 1, EwNewRect( 0, 0, 150, 150 ), 0 , 1 )
It is important to understand, that the bitmap treats the frames individually. It is thus not possible to copy an entire PNG content in multiple frames at once. Instead, you have to lock one frame and copy there the PNG contents. Then you lock another frame and copy there there contents.
Does it hep you?