About the PNG to BMP Converter
Plenty of long-lived Windows software predates PNG support, and the fix is almost always the same: hand it a bitmap. Splash screens for old installers, image fields in legacy database front ends, dialogue resources and certain CNC or embroidery packages all expect the uncompressed layout, and they expect the blue, green, red byte order that comes with it.
This converter writes precisely that. The header declares 24 bits per pixel with no compression, the rows run bottom to top, and each row is padded so its length is a multiple of four bytes, which is the rule that trips up hand-written encoders most often. Because there is no alpha channel in a 24-bit bitmap, any transparency in the PNG is composited onto the colour you select before the bytes are written.
The trade is size. A 1000 by 1000 PNG icon of 40 KB becomes about 3 MB as a bitmap, so keep these files local rather than shipping them over a network. If the receiving software has since learned newer formats, PNG to JPG or leaving the PNG alone will serve you far better.
How to use
- Select the PNG, including one with a transparent background if you have it.
- Set Flatten onto so cut-out areas take the right colour.
- Download the 24-bit bitmap.
Common questions
- Why does my transparent PNG come out with a solid background?
- A 24-bit bitmap has no alpha channel, so transparency must be painted onto a colour. Choose it in the Flatten onto menu.
- Is the pixel data identical to the PNG?
- Yes for opaque pixels. Nothing is re-compressed, so the values match what the PNG decoded to.
- Can old software open this file?
- It is the most widely supported BMP variant, uncompressed BI_RGB, so anything that claims BMP support should read it.
- How do I make the bitmap smaller?
- Reduce the pixel dimensions with the Max width menu. The format itself offers no compression worth using.