Hi Nikola, it definitely sounds like a bug in GIMP. If you want to report the bug, here's a description that you can send:



Bug in Pasting in CF_DIB format from the clipboard.

With a CF_DIB in the clipboard, that has biCompression of BI_RGB, the pixel values are not being read correctly, GIMP is incorrectly using the high byte of each pixel as an alpha value.

According to the documentation here (for BITMAPINFOHEADER): http://msdn.microsoft.com/en-us/library/windows/desktop/dd183376%28v=vs.85%29.aspx, for a 32-bit image using BI_RGB:

"If the biCompression member of the BITMAPINFOHEADER is BI_RGB, the bmiColors member of BITMAPINFO is NULL. Each DWORD in the bitmap array represents the relative intensities of blue, green, and red for a pixel. The value for blue is in the least significant 8 bits, followed by 8 bits each for green and red. The high byte in each DWORD is not used."

The problem is that Gimp is using the high byte as an alpha value when in this particular case it should be ignored and treated only as opaque alpha.

- Michael