BMP Bit Depth & Channel Workbench
Convert BMP bit depths, inspect indexed palettes and create RGB/BGR raw pixel exports. Preview 1/4/8/16/24/32-bit results with dithering, transparency and row-order controls.
1. Open & configure
No source image.
Channel, alpha & storage controls
Lower bit depths may reduce colors. All formats except 32-bit V4 flatten transparency. Raw channel order is chosen separately below.
2. Compare & export
Open an image or try the example.
Source pixels
Converted pixels
Create a bitmap to inspect the output.
Inspect the indexed palette
Create indexed output or open an indexed BMP to inspect its palette.
Raw pixels for developers
Exports the converted pixels, top-down, without row padding. The ZIP includes a format manifest so dimensions and channel order are clear.
Local processing with no file history. Ads and analytics follow our privacy information.
Using BMP Bit Depth & Channel Workbench
Convert BMP bit depths, inspect indexed palettes and create RGB/BGR raw pixel exports. Preview 1/4/8/16/24/32-bit results with dithering, transparency and row-order controls.
- Open an uncompressed Windows BMP or a PNG, JPEG or WebP image. Use the built-in gradient example to compare bit depths.
- Choose a target bit depth, palette settings and optional dithering. Advanced controls handle channels, alpha, background and top-down/bottom-up storage.
- Create the bitmap and inspect source/output previews and palette entries. Download BMP, the rendered PNG, palette CSV or raw pixel ZIP with a format manifest.
Example
24-bit preserves the processed RGB values. 32-bit V4 uses explicit alpha masks. Indexed and 16-bit formats can change colors; the report counts pixels changed by that conversion. Raw BGR exports write blue, green and red bytes for each pixel; they are not an incorrectly ordered BMP. The ZIP includes dimensions, row order and channel order.
Questions & answers
What does changing bit depth do?
It changes how pixels are stored. 1-bit uses two colors, 4-bit up to 16 palette colors, 8-bit up to 256, 16-bit reduces RGB channel precision, 24-bit stores full RGB and 32-bit V4 stores RGB plus explicit alpha.
Does lower bit depth preserve every color?
Only when the source colors fit the selected indexed palette and dithering is off. Otherwise colors are reduced; the converted preview and report show the result. Adaptive 8-bit output reuses the existing local GIF quality palette builder.
Can BMP store transparency?
This tool writes 32-bit V4 bitfield BMPs with an explicit alpha mask. Other output depths flatten transparency onto the chosen background. Some applications ignore BMP alpha; PNG preview export retains decoded alpha.
Which BMP inputs work?
Uncompressed Windows INFO/V2/V3/V4/V5 BMPs at 1, 4, 8, 16, 24 or 32 bits, including supported contiguous channel masks and top-down rows. RLE, OS/2 headers and embedded JPEG/PNG compression are rejected clearly.
What does RGB/BGR export mean?
Raw export creates channel bytes without a BMP header or row padding, in top-down order. Its ZIP contains data.bin and format.json. BMP exports always use their standard format layout.
Can I extract a BMP palette?
Yes. Select the embedded source palette or generated output palette. View every entry, copy hex colors or download CSV. True-color images do not contain an indexed palette.
What are the size limits?
BMP files up to 24 MiB; PNG/JPEG/WebP up to 20 MiB; decoded images up to 4 million pixels and 4,096 pixels per edge. Conversion is cancelable and runs locally.
Are files uploaded for processing?
No. Image decoding, palette conversion and ZIP packing run in your browser. Website ads and analytics follow the privacy information.
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