About the BMP to JPG Converter
Scanners, older cameras and industrial capture cards still hand out bitmaps, and those files are awkward to email or attach to a ticket. JPEG was designed for continuous tone photographs: it splits the picture into 8 by 8 blocks, transforms each one into frequency coefficients and throws away the fine detail the eye is least likely to miss. A photographic bitmap typically drops to two or three percent of its original weight at quality 90.
The quality dial runs from 1 to 100 and is passed straight to the browser encoder. Around 85 to 92 is the sweet spot for photographs; below 60 you begin to see blocking around edges and ringing next to text. Because JPEG has no alpha channel, any transparent area is painted onto the colour you pick under Flatten onto before encoding, which stops transparent regions turning black.
Keep the bitmap if the image is a diagram, a screenshot or line art, since JPEG smears hard edges. For those, BMP to PNG gives a smaller file and a cleaner result. Every conversion happens on your own machine, so confidential scans never leave the laptop.
How to use
- Choose the bitmap, or paste one straight from the clipboard.
- Set Quality, then watch the status line report the resulting file size.
- Save the JPG with the Download button once the size looks right.
Common questions
- What quality setting should I use?
- Start at 90. Drop to 75 when the file must fit an upload limit, and only go below 60 if size matters more than sharp edges.
- Why did my transparent corners turn white?
- JPEG cannot store transparency, so the tool flattens those pixels onto the colour chosen in the Flatten onto menu. Switch it to black or grey if white looks wrong.
- Can I convert several bitmaps at once?
- The tool works on one file at a time, but converting a second image is a single drag away and no page reload is needed.
- Does the tool strip the metadata?
- Yes. The bitmap is redrawn on a canvas, so nothing but the pixels reaches the JPG.