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For BMP Suite -version 2.3
- -This document describes the images in BMP Suite, and shows what -I allege to be the correct way to interpret them. PNG and JPEG images are -used for reference. -
- -It also shows how your web browser displays the BMP images, -but that’s not its main purpose. -BMP is poor image format to use on web pages, so a web browser’s -level of support for it is arguably not important.
- -| File | -Ver. | -Correct display | -In your browser | -Notes | -
|---|---|---|---|---|
| g/pal1.bmp | -3 | - |
- |
- 1 bit/pixel paletted image, in which black is the first color in - the palette. | -
| g/pal1wb.bmp | -3 | - |
- |
- 1 bit/pixel paletted image, in which white is the first color in - the palette. | -
| g/pal1bg.bmp | -3 | - |
- |
- 1 bit/pixel paletted image, with colors other than black and white. | -
| q/pal1p1.bmp | -3 | - |
- |
- 1 bit/pixel paletted image, with only one color in the palette. - The documentation says that 1-bpp images have a palette size of 2 - (not “up to 2”), but it would be silly for a viewer not to - support a size of 1. | -
| q/pal2.bmp | -3 | - |
- |
- A paletted image with 2 bits/pixel. Usually only 1, 4, - and 8 are allowed, but 2 is legal on Windows CE. | -
| g/pal4.bmp | -3 | - |
- |
- Paletted image with 12 palette colors, and 4 bits/pixel. | -
| g/pal4rle.bmp | -3 | - |
- |
- 4-bit image that uses RLE compression. | -
| q/pal4rletrns.bmp | -3 | -- or - or |
- |
- An RLE-compressed image that used “delta” - codes to skip over some pixels, leaving them undefined. Some viewers - make undefined pixels transparent, others make them black, and - others assign them palette color 0 (purple, in this case). | -
| g/pal8.bmp | -3 | - |
- |
- Our standard paletted image, with 252 palette colors, and 8 - bits/pixel. | -
| g/pal8-0.bmp | -3 | - |
- |
- Every field that can be set to 0 is set to 0: pixels/meter=0; - colors used=0 (meaning the default 256); size-of-image=0. | -
| g/pal8rle.bmp | -3 | - |
- |
- 8-bit image that uses RLE compression. | -
| q/pal8rletrns.bmp | -3 | -- or - or |
- |
- 8-bit version of q/pal4rletrns.bmp. | -
| g/pal8w126.bmp | -3 | - |
- |
- Images with different widths and heights. - In BMP format, rows are padded to a multiple of four bytes, so we - test all four possibilities. | -
| g/pal8w125.bmp | -3 | - |
- |
- |
| g/pal8w124.bmp | -3 | - |
- |
- |
| g/pal8topdown.bmp | -3 | - |
- |
- BMP images are normally stored from the bottom up, but - there is a way to store them from the top down. | -
| q/pal8offs.bmp | -3 | - |
- |
- A file with some unused bytes between the palette and the - image. This is probably valid, but I’m not 100% sure. | -
| q/pal8oversizepal.bmp | -3 | - |
- |
- An 8-bit image with 300 palette colors. This may be invalid, - because the documentation could - be interpreted to imply that 8-bit images aren’t allowed - to have more than 256 colors. | -
| g/pal8nonsquare.bmp | -3 | -
- - or -
- |
- |
- An image with non-square pixels: the X pixels/meter is twice - the Y pixels/meter. Image editors can be expected to - leave the image “squashed”; image viewers should - consider stretching it to its correct proportions. | -
| g/pal8os2.bmp | -OS/2v1 | - |
- |
- An OS/2-style bitmap. | -
| q/pal8os2sp.bmp | -OS/2v1 | - |
- |
- An OS/2v1 with a less-than-full-sized palette. - Probably not valid, but such files have been seen in the wild. | -
| q/pal8os2v2.bmp | -OS/2v2 | - |
- |
- My attempt to make an OS/2v2 bitmap. | -
| q/pal8os2v2-16.bmp | -OS/2v2 | - |
- |
- An OS/2v2 bitmap whose header has only 16 bytes, instead of the full 64. | -
| g/pal8v4.bmp | -4 | - |
- |
- A v4 bitmap. I’m not sure that the gamma and chromaticity values in - this file are sensible, because I can’t find any detailed documentation - of them. | -
| g/pal8v5.bmp | -5 | - |
- |
- A v5 bitmap. Version 5 has additional colorspace options over v4, so it - is easier to create, and ought to be more portable. | -
| g/rgb16.bmp | -3 | - |
- |
- A 16-bit image with the default color format: 5 bits each for red, - green, and blue, and 1 unused bit. - The whitest colors should (I assume) be displayed as pure white: - (255,255,255), not - (248,248,248). | -
| g/rgb16-565.bmp | -3 | - |
- |
- A 16-bit image with a BITFIELDS segment indicating 5 red, 6 green, - and 5 blue bits. This is a standard 16-bit format, even supported by - old versions of Windows that don’t support any other non-default 16-bit - formats. - The whitest colors should be displayed as pure white: - (255,255,255), not - (248,252,248). | -
| g/rgb16-565pal.bmp | -3 | - |
- |
- A 16-bit image with both a BITFIELDS segment and a palette. | -
| q/rgb16-231.bmp | -3 | - |
- |
- An unusual and silly 16-bit image, with 2 red bits, 3 green bits, and 1 - blue bit. Most viewers do support this image, but the colors may be darkened - with a yellow-green shadow. That’s because they’re doing simple - bit-shifting (possibly including one round of bit replication), instead of - proper scaling. | -
| q/rgba16-4444.bmp | -5 | - |
- |
- A 16-bit image with an alpha channel. There are 4 bits for each color - channel, and 4 bits for the alpha channel. - It’s not clear if this is valid, but I can’t find anything that - suggests it isn’t. - | -
| g/rgb24.bmp | -3 | - |
- |
- A perfectly ordinary 24-bit (truecolor) image. | -
| g/rgb24pal.bmp | -3 | - |
- |
- A 24-bit image, with a palette containing 256 colors. There is little if - any reason for a truecolor image to contain a palette, but it is legal. | -
| q/rgb24largepal.bmp | -3 | - |
- |
- A 24-bit image, with a palette containing 300 colors. - The fact that the palette has more than 256 colors may cause some viewers - to complain, but the documentation does not mention a size limit. | -
| q/rgb24prof.bmp | -5 | - |
- |
- My attempt to make a BMP file with an embedded color profile. | -
| q/rgb24lprof.bmp | -5 | - |
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- My attempt to make a BMP file with a linked color profile. | -
| q/rgb24jpeg.bmp | -5 | - |
- |
- My attempt to make BMP files with embedded JPEG and PNG images. - These are not likely to be supported by much of anything (they’re - intended for printers). | -
| q/rgb24png.bmp | -5 | - |
- |
- |
| g/rgb32.bmp | -3 | - |
- |
- A 32-bit image using the default color format for 32-bit images (no - BITFIELDS segment). There are 8 bits per color channel, and 8 unused - bits. The unused bits are set to 0. | -
| g/rgb32bf.bmp | -3 | - |
- |
- A 32-bit image with a BITFIELDS segment. As usual, there are 8 bits per - color channel, and 8 unused bits. But the color channels are in an unusual - order, so the viewer must read the BITFIELDS, and not just guess. | -
| q/rgb32fakealpha.bmp | -3 | -- or -
- |
- |
- Same as g/rgb32.bmp, except that the unused bits are set to something - other than 0. - If the image becomes transparent toward the bottom, it probably means - the viewer uses heuristics to guess whether the undefined - data represents transparency. | -
| q/rgb32-111110.bmp | -3 | - |
- |
- A 32 bits/pixel image, with all 32 bits used: 11 each for red and - green, and 10 for blue. As far as I know, this is perfectly valid, but it - is unusual. | -
| q/rgba32.bmp | -5 | - |
- |
- A BMP with an alpha channel. Transparency is barely documented, - so it’s possible that this file is not correctly formed. - The color channels are in an unusual order, to prevent viewers from - passing this test by making a lucky guess. | -
| q/rgba32abf.bmp | -3 | - |
- |
- An image of type BI_ALHPABITFIELDS. Supposedly, this was used on - Windows CE. I don’t know whether it is constructed correctly. | -
| b/badbitcount.bmp | -3 | -N/A | - |
- Header indicates an absurdly large number of bits/pixel. | -
| b/badbitssize.bmp | -3 | -N/A | - |
- Header incorrectly indicates that the bitmap is several GB in size. | -
| b/baddens1.bmp | -3 | -N/A | - |
- Density (pixels per meter) suggests the image is much - larger in one dimension than the other. | -
| b/baddens2.bmp | -3 | -N/A | - |
- |
| b/badfilesize.bmp | -3 | -N/A | - |
- Header incorrectly indicates that the file is several GB in size. | -
| b/badheadersize.bmp | -? | -N/A | - |
- Header size is 66 bytes, which is not a valid size for any known BMP - version. | -
| b/badpalettesize.bmp | -3 | -N/A | - |
- Header incorrectly indicates that the palette contains an absurdly large - number of colors. | -
| b/badplanes.bmp | -3 | -N/A | - |
- The “planes” setting, which is required to be 1, is not 1. | -
| b/badrle.bmp | -3 | -N/A | - |
- An invalid RLE-compressed image that tries to cause buffer overruns. | -
| b/badwidth.bmp | -3 | -N/A | - |
- The image claims to be a negative number of pixels in width. | -
| b/pal8badindex.bmp | -3 | -N/A | - |
- Many of the palette indices used in the image are not present in the - palette. | -
| b/reallybig.bmp | -3 | -N/A | - |
- An image with a very large reported width and height. | -
| b/rletopdown.bmp | -3 | -N/A | - |
- An RLE-compressed image that tries to use top-down orientation, - which isn’t allowed. | -
| b/shortfile.bmp | -3 | -N/A | - |
- A file that has been truncated in the middle of the bitmap. | -