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IrfanView shows 8 BPP but it should be 1 BPP

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    Reported IrfanView shows 8 BPP but it should be 1 BPP

    This bug is about Wireless Bitmaps (WBMP) in IrfanView.

    I'm playing around with WBMP just for the fun and learning the history of computer graphics.

    I was reading at the oldschool WAP specification, and learned that a WBMP image file uses 1 BPP.
    Please read it over here: on page 11.

    The specification is saying:
    WBMP type 0 has the following characteristics:•No compression•Colour: one bit represents a pixel (white=1, black=0). •Depth: 1 bit deep (monochrome) •The high bit of each byte is the left-most pixel of the byte.•The first row in the data is the upper row of the image.

    Then I was looking for a test WBMP file to see how IrfanView displays it. I found one on this webpage: the direct link to the WBMP image is:

    When I open it in Irfanview 4.54 - 64 Bit it says at the bottom:
    800 x 600 x 8 BPP.

    Click image for larger version

Name:	wbmp.jpg
Views:	1
Size:	427.7 KB
ID:	85324

    When I open the Image properties, IrfanView shows: 256 (8 BitsPerPixel) at the Original colors.

    Now, I want to talk about the 8 BPP, because it contradicts the specification.
    The question I have is: is IrfanView showing the wrong BPP or is it something else ??

    Kind regards,
    Last edited by julekker; 27.07.2020, 06:15 AM.