BMP to PNG Image Converter

What this page does

This page converts BMP images to PNG. The output opens on PNG, and you can add several bitmaps, set quality and optionally resize. The server writes a PNG for each upload and returns a download.

Both formats can store an image without lossy compression, but PNG is far more practical. It compresses the data, supports alpha cleanly and is accepted by modern browsers, editors and document tools. BMP is simple but heavy.

Why convert BMP to PNG

The main reason is size. A BMP often stores pixels with little compression, so a large bitmap can be many times bigger than the same image as PNG. Converting to PNG usually reduces the file while keeping the pixels exact.

PNG is also a better editing and delivery format. It supports transparency, works in browsers and design tools, and does not add the generation loss of JPEG. For screenshots, logos, diagrams and line art, it is the natural choice.

PNG is not always smaller for every image. A noisy photo can compress poorly, and a JPEG may be the better delivery format for photographs. Compare the actual files if size is the priority.

Lossless, but not magic

BMP to PNG is generally a lossless conversion: the pixels are preserved, and the PNG container stores them more efficiently. It does not add detail or repair a low-quality source. If the BMP is a scan with noise, the PNG keeps that noise.

PNG's compression is also different from JPEG's. It looks for repeated patterns rather than discarding detail, so flat graphics and screenshots shrink well, while photographic noise may not.

Transparency and colour

PNG supports alpha, but the source BMP may not have a usable alpha channel. If the BMP has transparency, check that the conversion keeps it. If the BMP was flattened onto a colour, PNG cannot remove that background automatically.

Colour profiles and bit depth can change during conversion. For critical brand work, compare the PNG with the BMP on the same screen. If the BMP is a legacy 8-bit image, the PNG preserves that limited palette rather than inventing new colours.

Editing and compatibility

PNG opens in modern photo editors, vector-adjacent design tools, office suites and browsers. That makes it a good handoff when the source is an old bitmap that only a legacy program can read. You can edit the PNG without another lossy step.

Some very old devices may accept BMP but not PNG. If the destination is one of them, keep the BMP; otherwise PNG is the safer modern copy.

Batch workflow

Add the files, keep PNG selected, set any resize options and process. Each file is handled separately, and there is no ZIP bundle. Download the results one by one.

Test a photo and a flat graphic before converting a mixed folder. The photo may be smaller as JPEG, while the graphic is likely smaller and cleaner as PNG.

When not to use PNG

Do not use PNG for large photographic galleries where JPEG or WebP would be much smaller. Do not use it as a print master without checking the resolution; PNG preserves pixels but does not add them. For a photo archive, keep the original camera file if you have it.

Limits and privacy

Files are uploaded to the server for conversion. Do not send private documents or client images to a public converter. The page does not offer a local-only mode.

Large bitmaps and long batches can hit upload or memory limits. Keep the BMP originals until the PNGs have been checked.

PNG for screenshots and line art

PNG is the natural format for screenshots, diagrams, logos and images with text. It keeps sharp edges and flat colour without the blocking that JPEG introduces. It also supports alpha, so a cut-out subject can keep a clean background.

A BMP screenshot converted to PNG usually becomes much smaller and easier to share. A BMP photo may also shrink, but a JPEG or WebP could be smaller still.

Preparing a legacy bitmap

Check the bitmap dimensions before converting. A very large bitmap may exceed upload limits even after PNG compression. Resize to the size the page or document needs, and keep the original if you may need a larger version later.

If the bitmap has a colour table, the PNG keeps those colours. It does not invent a wider palette. That is fine for a legacy graphic and a limitation for a photo that was saved with too few colours.

PNG versus JPEG and WebP

Use PNG when sharp edges, text or transparency matter. Use JPEG for photographs and smaller email attachments. Use WebP for efficient web delivery when the destination supports it. Converting a BMP to PNG is a safe default for editing, but it is not always the smallest delivery file.

Compression expectations

PNG compresses repeated patterns, so flat graphics, screenshots and line art often shrink a lot. A photograph with noise may shrink less, and a JPEG or WebP could beat it on size. The conversion is still useful because it preserves the pixels and gives you a modern editing file.

Do not judge the result by the BMP size alone. Compare the PNG with a JPEG export at a reasonable quality and choose the format that fits the destination.

Archiving the PNG

Keep the PNG as a lossless working copy, but do not discard the original camera or design file if you have it. PNG preserves pixels, not the editing history. For a legacy bitmap with no other source, the PNG is a safer long-term copy than the BMP because it is smaller and more widely supported.

Common problems

A PNG may look identical to the BMP but still be rejected by an old device that expects BMP. A transparent area may turn black or white if the source alpha was not usable. A photo may be larger than expected because PNG does not discard detail. Check the destination and the actual bytes.

If the PNG is for the web, compare it with a WebP export. PNG is the safer editing copy, but WebP may be the smaller delivery file.

Keep the file name stable and note the source bitmap, so a later edit does not start from the wrong copy.

Keep the original bitmap until the PNG has been checked on the target.

Frequently Asked Questions