BMP vs PNG and JPG: Why Use an Uncompressed Format at All

Three formats, three philosophies

To grasp the difference, you need to see the intent, not a spec sheet. Each of the three formats solved its own problem in its own time.

• BMP (1980s) was born with Windows, when on-the-fly compression was expensive for weak processors. Its principle: store pixels exactly as they sit in memory. Opening fast mattered more than weighing little.
• JPG (1992) was built for photographs and the internet. Its principle: throw away the details the eye barely notices, and shrink the file by tens of times. Compression with loss.
• PNG (1996) was created as a free replacement for the old GIF. Its principle: compress with zero loss and add honest transparency. Ideal for graphics, logos and screenshots.

In other words, BMP is the "raw material," JPG is a "compact copy for the eye," and PNG is a "tidy lossless archive." The whole comparison flows from these three ideas.

File size: the main battle

Here BMP loses outright, and by a crushing margin. Let's run the numbers on a concrete example — a 4000×3000-pixel photo (12 megapixels, a typical phone shot):

The math of BMP is simple and merciless: 4000 × 3000 pixels × 3 bytes = 36 million bytes, i.e. ~36 MB — and that is before palette and headers. PNG will compress the same shot about threefold without losing a single pixel. And JPG, with its "smart loss," fits the photo into 2–4 MB, with a difference all but invisible to the eye.

For photographs the gap is especially wide: JPG here is 10–15 times lighter than BMP. For graphics with few colors, PNG wins. BMP never wins on size.

Quality: loss and the lack of it

On quality, though, the picture is no longer one-sided. Here it matters to distinguish two kinds of compression.

BMP and PNG are lossless. They store the image exactly: every pixel of the original stays in place. The only difference is that PNG does it compactly while BMP does it wastefully. On quality they are equal: converting BMP → PNG loses nothing.

JPG is lossy. It deliberately coarsens the picture, discarding small details. On a photo this is invisible, but on sharp edges, text and flat areas it produces artifacts — blurry "halos" around letters and blockiness. That is why JPG is ideal for photos and poor for screenshots with text.

The comparison table

Let's gather the key differences in one place:

When BMP is justified after all

Despite the rout on size, BMP has honest scenarios where it suits the task better than its rivals:

• Old and niche software. Some programs and devices can read only BMP — for them it is the single "common language."
• Embedded systems. A microcontroller finds it easier to output a "raw" BMP than to spend resources unpacking a PNG.
• A guarantee of no compression. In scientific and medical work it sometimes matters that the data passed through no algorithm at all — not even a lossless one.
• Intermediate exchange. As a temporary format between processing stages, where read speed matters more than size.

Notice that all these cases are about hardware and special tasks, not everyday storage or publishing. For people and the internet, BMP always loses.

What to pick for your task

A short cheat sheet that covers 95% of real situations:

How to move off BMP without loss

If you have a heavy BMP on your hands, moving to a modern format takes seconds and needs no software. For graphics pick PNG (quality is preserved exactly); for photos pick JPG (the weight drops the most).

For photos, converting BMP to JPG is more efficient. And if you want to understand more deeply why BMP is so bulky, read how the file is built inside, or start with the basics — what BMP is. All conversion options are gathered on the all formats page.