Why show image code doesn't run ?

[Glus Xof <gtglus gmail com>]

Hi guys,

Trying to implement the conclusions of the last thread (related on buffer pixels storing), I encountered another very strange situation...

While Code A (pastebin.com/3K6P5X9g) runs perfectly...  Code B (pastebin.com/nrbNTZzH) doesn't...

Why this code B fails ?

Glus