PNG to JPG — When You Should Convert (and When You Shouldn't)
You have a PNG. It's 3 MB. The form you're trying to upload it to has a 1 MB limit, or your inbox is rejecting attachments, or your portfolio's page-weight budget is screaming. The instinct is to convert PNG to JPG, because JPGs are smaller. Most of the time that works. Sometimes it produces an image that's visibly worse than the original, and you'd rather have shrunk the PNG.
The difference comes down to what's in the PNG.
PNG vs. JPG — a quick model that's actually useful
PNG is lossless: it stores every pixel, exactly. It's good at flat colour, sharp edges, and transparency. Logos. Screenshots. Diagrams. Anything with text rendered onto a solid background.
JPG is lossy: it represents the image as frequencies and discards detail your eye is bad at noticing. It's good at photographs — gradient skies, skin tones, foliage — where blocky compression artefacts hide in the visual noise. It's bad at sharp edges and flat colour, where the artefacts have nothing to hide behind.
Practical rule:
- Photo in a PNG → convert to JPG. Big size win, no visible quality loss.
- Screenshot, logo, diagram, chart, text-on-solid-background in a PNG → keep as PNG. Convert to JPG and you'll see compression haloes around every letter and edge.
Convert in your browser
Buncha's Bulk Image Converter reads PNG and writes JPG entirely client-side. Drop one file or a folder; pick JPG; pick a quality (85% is the usual sweet spot); download. No upload, no account.
If you'd rather keep the format and just shrink the file, the Image Compressor does that — particularly useful for screenshots that need to stay PNG but are too big.
What "quality" means
JPG export accepts a quality number from 1 (worst) to 100 (best). The values that matter:
- 95+ — very large file, identical to the eye. Use only when you're going to re-edit.
- 85 — the default in most software. ~30% smaller than 95, and you cannot tell.
- 75 — the floor for photos you care about. Compression starts being visible on close inspection.
- 60 and below — visible artefacts. Use only for thumbnails or aggressive size budgets.
A typical photo PNG at 8 megapixels is around 6–10 MB. The same image at JPG quality 85 is around 1–2 MB. Quality 75 is around 700 KB.
The transparency problem
JPG doesn't support transparent pixels. Convert a PNG with a transparent background and the JPG will fill that area with white (or your converter's chosen background colour). For logos, product cutouts, or anything with see-through areas, this is the opposite of what you want — the conversion ruins the file. Stay with PNG, or use Background Remover if you actually want a clean cutout.
Browser-side, why
Server-side converters upload your image, convert it, and let you download. That model means:
- Your file is on someone else's server for some retention window.
- Most free tiers are rate-limited (X conversions per day) or watermark the output.
- A 10 MB photo takes longer to upload than to actually convert.
Browser conversion via <canvas> is instant per file and never leaves your device. There's no account, no quota, no privacy question to think about.
Bulk works the same
If you have a folder of PNGs from a camera dump, screenshots, or a design export, drop the whole set into the bulk converter. It processes them one at a time and offers a single ZIP download at the end. Naming is preserved (each .png becomes the same name with .jpg).
The shortest path
Open the converter, drop the PNG in, pick JPG, pick quality 85, download. If the result looks worse than expected, your source was probably a screenshot or logo — go back and shrink the PNG instead.