How to Convert BMP to PNG: Step-by-Step Tutorial

By Bill Crawford  ·  March 2026  ·  6 min read  ·  Last updated March 6, 2026

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What This Tutorial Covers

This tutorial walks you through converting BMP images to lossless PNG format using the browser-based tool on this site. No software installation required. You will learn how to add files, understand the per-file status system, use batch ZIP download, and deploy your PNG output for web use.

For background on why you might want PNG and when to use it over JPG or WebP, see the companion BMP to PNG Complete Guide.

What You Need

• One or more .bmp files
• A modern browser: Chrome, Edge, Firefox, or Safari (2022 or later)
• No account, no software, no subscription

Step 1: Open the Converter

Navigate to dataconversioncenter.com/image-tools/bmp-to-png/. The page loads JSZip from CDN for the ZIP download feature — no other libraries are needed because BMP decoding and PNG encoding are handled natively by the browser's HTML Canvas API.

Step 2: Add Your BMP Files

You have two ways to add files:

• Drag and drop: Open your file manager and drag one or more .bmp files directly onto the drop zone labeled "Drop BMP files here". The zone highlights in blue when you hover over it.
• Browse: Click anywhere on the drop zone (or the "Browse Files" link) to open your file picker. Select multiple files using Ctrl+click (Windows) or Cmd+click (Mac).

As soon as files are added, the tool generates thumbnail previews for each one. You will see an Input Files grid with a card per file showing the filename, file size, and a Ready status badge.

Note: Files with an extension other than .bmp are automatically rejected with an inline error message. They are not added to the conversion queue.

Step 3: Choose Download Mode

Before converting, decide how you want to download your PNG files:

• Individual downloads (default): Leave "Download as ZIP" unchecked. After conversion, each output card has its own Download button, and a "Download All PNGs" button appears for sequential bulk download.
• ZIP archive: Check "Download as ZIP". After conversion, a single "Download ZIP" button downloads all PNGs in one file named dataconversioncenter_bmp_to_png_YYYYMMDDHHMM.zip using your local date and time.

For batches of more than 5 files, the ZIP option is strongly recommended to avoid multiple browser download dialogs.

Step 4: Click "Convert to PNG"

Click the blue Convert to PNG button. The button label changes to "Converting…" and is disabled while conversion runs.

For each file in sequence:

1. The status badge on the input card changes from Ready to Converting…
2. The browser loads the BMP into an HTML Image element and draws it to an HTML Canvas at the native resolution.
3. The Canvas API's toBlob('image/png') method encodes the canvas pixel data as a lossless PNG blob in memory.
4. The status changes to Converted and an output card appears.

The progress bar tracks overall progress — "Converted X of N". Files are processed two at a time for throughput efficiency.

Step 5: Review the Results

After conversion completes, a summary banner appears: "✓ All N files converted successfully" or "Completed: X succeeded, Y failed."

An Output Files grid displays cards for each successfully converted PNG, showing:

• A thumbnail preview of the output
• The output filename — same base name as the input with .png extension (e.g. screenshot.bmp → screenshot.png)
• Output file size (typically 30–60% smaller than the source BMP)
• A per-file Download PNG button

Any files that failed to convert are marked with a red Error badge. This is uncommon but can happen with very old or malformed BMP files that the browser's image decoder cannot parse. The tool continues converting remaining files when one fails.

Step 6: Download Your PNGs

Individual download

Click the ⬇ Download PNG button on any output card to save that file. The filename is the same as the input with .png extension.

Download All (no ZIP)

With "Download as ZIP" unchecked, click Download All PNGs. The tool triggers sequential browser downloads with a 120 ms delay between each to prevent browser throttling.

Download ZIP

With "Download as ZIP" checked, click Download ZIP. JSZip assembles all PNG blobs in memory and downloads a single file named, for example, dataconversioncenter_bmp_to_png_202603061200.zip.

Step 7: The Tool Resets Automatically

After a ZIP download or "Download All" completes, the tool automatically resets to its initial empty state. All thumbnails, cards, and file references are cleared. The checkbox resets to unchecked. Click Start Over to reset manually at any point.

Bonus: Using Your PNG on the Web

PNG files are immediately web-ready. Here are some common next steps:

1. Embed in HTML: <img src="screenshot.png" alt="Description"> — browsers render PNG natively with no plugin or conversion needed.
2. Upload to a CMS: WordPress, Squarespace, Webflow, and virtually every CMS accept PNG natively.
3. Use in Figma or design tools: Drag the PNG directly onto the canvas — all major design tools support PNG without an import step.
4. Share via email: Unlike BMP, PNG attachments do not trigger spam filters and display inline in every email client.

If you need even smaller files for web delivery, consider running the PNG through Image Compressor for lossless size optimization, or converting to WebP for maximum web compression.

Troubleshooting

• File shows Error status: Verify the file is a genuine BMP. Some image editors save files with a .bmp extension that are actually a different format. Try opening the file in a viewer to confirm it renders correctly before converting.
• Thumbnails not generating: Very large BMPs (50+ MB) may take a few seconds to decode in the browser. The tool will proceed when ready.
• Output PNG is larger than expected: PNG is lossless — for photographic BMPs, it may be only modestly smaller than the source. For maximum compression with photos, use BMP to JPG or BMP to WebP instead.
• ZIP not downloading: Some browsers require a direct user interaction to trigger downloads. Ensure you clicked the Download ZIP button directly rather than via a script or automation.
• Colors look different in PNG: This is extremely rare with BMP-to-PNG conversion since both use standard RGB color spaces. If you see color differences, check that your monitor color profile is consistent between the applications you are comparing.

Next Steps After Conversion

• Compress for web: Use Image Compressor to apply additional lossless PNG compression before deploying to a website.
• Resize for specific targets: Use Image Resizer to scale the PNG to specific pixel dimensions for social media, app stores, or responsive web layouts.
• Convert to WebP for maximum web performance: If you are optimizing for web page load speed and all your target browsers are modern, convert to WebP for smaller files.
• Need other BMP conversions? Try BMP to JPG for photos, BMP to ICO for icons, or BMP to AVIF for next-gen web images.

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