I made little the analyse of problem.

Problem has two parts.
At first it is refresh of image surface.
It is not bug in unDelphiX. The concept no compute with change the picture in DDS, but prefer direct drawing. ClearStack dramatically suspend speed of drawing, I no advice it (so only for special purpose).

And second it is drawing...using DrawAlpha, DrawAdd and etc.
I think that it can be bug. I did track all the calls low level routines to DirectX and all returned with DD_OK flag (I am using last published version 1.07b). But pictures no show! This can be the same bug that picture is drawing on empty Surface. But I don't know best solution.

You can use ...

1/ technique of videotexture like Hori's sample

2/ predefined picture and draw it throught DXImageList (from one picture)

3/ directly drawing via DXDraw.Surface[.Canvas]

4/ own another technique for me unknown

Many clever and handy programmers are here.
Can anybody help us with this problem? For better unDelphiX? Thanks!