BMP vs PNG
| Property | BMP | PNG |
|---|---|---|
| Full name | Bitmap image (Windows BMP / DIB) | Portable Network Graphics |
| File extensions | .bmp, .dib | .png |
| Created by | Microsoft (with IBM for OS/2) | PNG Development Group (W3C Recommendation) |
| Introduced | Late 1980s | 1996 |
| Compression | Usually none: raw pixels, so files are huge | Lossless: every pixel is kept exactly |
| Transparency | Only in rare 32-bit variants that few apps honour | Yes, full alpha channel with soft edges |
| Animation | No | Only as APNG, which few apps play |
| Typical size | About 36 MB for a 12-megapixel photo | Often 3–10× larger than JPG for photos; small for flat graphics |
| Opens on | Windows apps and all browsers; most upload forms reject it or choke on the size | Every browser, phone, computer and image editor |
| Best for | Old Windows software, scanners and raw pixel data | Screenshots, logos, text and graphics with transparency |
Why convert BMP to PNG?
PNG is the lossless choice for bitmaps. The pixels in the PNG are exactly the pixels in the BMP, so it suits anything you may edit again or where sharp detail matters: screenshots from old software, pixel art, UI mock-ups, technical drawings, scanned line art and sprites for games.
How much you save depends on the picture. Flat colours and repeated patterns compress extremely well, often to a tenth of the BMP or less. Photos and noisy scans compress less, typically to about half or a third, because PNG cannot throw away detail. For photos, BMP to JPG gives much smaller files at a quality you will not tell apart.
PNG also opens everywhere BMP does and many places it does not, such as websites, Google Docs, Slack and most upload forms.