From megabytes to kilobytes
An uncompressed BMP photo weighs whatever its pixels weigh — a 12-megapixel scan is 36 MB, period. JPG compresses photographic content so efficiently that the same scan becomes 1–2 MB at 90% quality with no visible difference. That's the difference between "attachment too large" and done.
Pick JPG for photos and scans; if your bitmap is a screenshot, diagram or anything with sharp text edges, BMP to PNG keeps those edges perfectly crisp. Everything converts in your browser — no upload, no queue, no limits.
Frequently asked questions
What quality setting should I use?
90% is visually identical for photos and scans. Drop lower only if you need the absolute smallest files.
When should I pick PNG instead?
For screenshots, diagrams and text — JPG softens sharp edges. For photos, JPG is the right choice and dramatically smaller.
What happens to transparency?
JPG has no transparency, so transparent areas (rare in BMP, but possible in 32-bit files) are filled with white.