Free online BMP to PNG converter

Websites, document systems, and messaging tools often reject .bmp uploads or make them impractical because BMP files are large. Saving as PNG usually preserves the image pixels while producing a more widely accepted file with lossless compression.

What BMP files contain

BMP (Bitmap) is a raster-image format closely associated with Microsoft Windows. Windows Paint, older Windows programs, scanners, screen-capture tools, and industrial or legacy applications may create .bmp files.

Many BMP files store uncompressed pixel data, so screenshots, diagrams, and scans can be much larger than equivalent PNG files. BMP supports several pixel layouts, including indexed color, 16-bit and 24-bit RGB, 32-bit data, bitfields, and some run-length compression variants; support for alpha transparency and metadata differs between applications.

What PNG files offer

PNG (Portable Network Graphics) is a lossless raster format using DEFLATE compression. It is supported by current web browsers, operating systems, office applications, image editors, and publishing software.

PNG can store indexed color, grayscale, truecolor, and an alpha channel for partial transparency. It is usually efficient for screenshots, icons, interface graphics, line art, and diagrams; for photographs, a PNG may remain larger than a JPEG or WebP file because PNG does not discard image data.

Convert a BMP file to PNG

Use the BMP-to-PNG converter on 101convert.com to convert a file without installing software. Upload the .bmp file, start the conversion, download the .png result, and open it once before deleting the original.

Convert locally with Paint, GIMP, or ImageMagick

For a standard BMP on Windows Paint, open the file and select File → Save as → PNG picture. Enter a filename ending in .png and save it. Paint is suitable for simple images, but it may not retain every metadata field or unusual BMP transparency arrangement.

For palette conversion, cropping, color correction, or transparency inspection, open the image in GIMP and select File → Export As. Set the output name to image.png, select Export, and retain the default PNG settings unless a receiving system specifies otherwise.

For scripts and batch work, ImageMagick can convert one file with:

magick input.bmp output.png

In Windows PowerShell, convert BMP files in the current folder with:

Get-ChildItem -File *.bmp | ForEach-Object { magick $_.FullName ($_.BaseName + '.png') }

Quality and compatibility limits

The conversion is normally lossless for decoded pixel data: PNG compression itself does not add JPEG-style artifacts. Do not resize the image or reduce its color depth during export if exact appearance is required.

Converting to PNG does not create transparency that is absent from the source. Check icons, game assets, and images with transparent edges after conversion, because uncommon 32-bit BMP alpha layouts may be interpreted differently by basic tools.

PNG cannot add resolution or recover detail missing from a low-quality scan or screenshot. For unusual 16-bit, palette-based, RLE-compressed, or bitfield BMP files, use GIMP or ImageMagick and compare the converted image with the original before using it in production.