BeRoPNG - A very tiny but complete PNG loader

[BeRo]

word and $FFFF0000 === 0 -- ALWAYS
word shl 16 === 0 -- ALWAYS.

Sorry, you're wrong. See my code again:

function Swap32(x:word):word;
begin
 result:=(Swap16(x and $ffff) shl 16) or Swap16((x and $ffff0000) shr 16);
end;

The first swap16 call gets "x and $ffff", and the result of it will shifted 16 bits to left, which's correct.
The second swap16 call gets "(x and $ffff0000) shr 16" or short "x shr 16", and the result of it will not shifted because it was already shifted 16 bits to right, which's also correct.

I guess, you had simply overlook the correct nested levels of the (...) blocks in my code.