Why convert PNG to JPG?
PNG (Portable Network Graphics) is a lossless format that stores every pixel exactly and supports transparency, which makes it perfect for logos, screenshots, and graphics with sharp edges. The trade-off is file size: a full-color photograph saved as PNG can be several times larger than the same image saved as JPG. When you need to email a picture, upload it to a website, or attach it to a document, that extra weight slows everything down and can push you past upload limits.
JPG (also written JPEG) uses lossy compression tuned for photographs and natural imagery. By discarding detail the human eye barely notices, it produces dramatically smaller files while keeping photos looking crisp. Converting a PNG photo to JPG routinely cuts the file size by 60–90%, which is why JPG remains the default choice for cameras, social media, and the web.
Pixohub converts PNG to JPG entirely inside your browser using the HTML canvas API. Because there is no server round-trip, conversion is instant, completely private, and works even on slow connections. Transparent areas of the PNG are automatically filled with a white background, since JPG does not support transparency.
PNG vs JPG: which should you use?
Choose PNG when transparency matters or when you need pixel-perfect quality — think icons, UI elements, diagrams, and text-heavy screenshots. Choose JPG for photographs, thumbnails, hero images, and anything where a small file size is more important than perfect fidelity. If you are publishing to the web and the image is a photo, JPG almost always wins on performance.
A common workflow is to keep a master PNG for archiving and export a JPG copy for sharing. With Pixohub you can do exactly that in seconds, and because everything runs locally you can convert sensitive screenshots or private photos without ever uploading them to a third-party service.
PNG vs JPG: technical differences
The real difference is in what each encoder is willing to throw away. PNG's DEFLATE compression finds repeated byte patterns and keeps every pixel, so it is brilliant on flat UI colours and hopeless on camera noise. JPG splits the picture into 8×8 blocks, converts them to frequencies and rounds the fine detail away. On a 12-megapixel photo that difference is dramatic: a PNG of 15–25 MB typically becomes a 2–4 MB JPG at quality 85, with no change you can see at normal viewing size.
Screenshots behave very differently. A 1920×1080 screenshot of a website might be 300 KB as PNG and only shrink to around 200 KB as JPG — while picking up faint grey 'mosquito' noise around every letter. Browser JPG encoders also usually store colour at half resolution (4:2:0 chroma subsampling), which is why thin red or blue text can look smeared after conversion even at high quality.
Bit depth is another quiet change. PNG can hold 16 bits per channel; baseline JPG is 8-bit, and Pixohub works on an 8-bit canvas anyway, so a 16-bit PNG from a scanner or a RAW developer is reduced to 8 bits. For a photo that is invisible; for a heavily edited gradient it can occasionally show as slight banding.
| PNG (Portable Network Graphics) | JPG (JPEG (Joint Photographic Experts Group)) | |
|---|---|---|
| Compression | Lossless (DEFLATE with per-row prediction filters) | Lossy (8×8 DCT blocks, quantisation, chroma subsampling) |
| Colour depth | 1–16 bits per channel; truecolor, greyscale or 256-colour palette | 8 bits per channel; RGB/YCbCr, greyscale or CMYK |
| Transparency | Full 8/16-bit alpha channel | None |
| Animation | Only via the APNG extension | None |
| Metadata | Text chunks, ICC profile, gamma; EXIF via the newer eXIf chunk | EXIF, IPTC, XMP, ICC profile |
| Typical file size | Large for photos (often 2–3× a JPG); tiny for flat graphics | Smallest of the classic formats for photos |
| Support | Universal — every browser, OS and editor | Universal — every browser, camera and device |
When to convert PNG to JPG
Shrinking phone screenshots before emailing them
Phones save screenshots as PNG, and a long scrolling capture from a modern phone can easily pass 3–5 MB. If the screenshot is mostly photos (a social feed, a product gallery), converting to JPG at 80–85% cuts it to a fraction of that and keeps attachments under mail-server limits. If it is mostly text, such as a chat or a receipt, keep PNG or use 90%+ quality so the letters stay clean.
Meeting a JPG-only upload form
Visa portals, job applications, insurance claims and older school systems often accept only .jpg and cap uploads at 1–2 MB. A PNG photo exported from an editor is usually both the wrong type and too large. Converting fixes the type; if it is still over the cap, follow up with the image compressor rather than repeatedly lowering the quality slider here.
Product photos that were saved as PNG by mistake
Sellers often export product shots from Canva or Photoshop as PNG because it is the default. For a photographed product on a white or styled background, JPG loads faster on the listing page and takes less of the marketplace's storage limit. Products cut out on a transparent background are the exception — those will gain a white background as JPG, which is usually what marketplaces want anyway.
Preparing images for print kiosks and photo labs
Many high-street photo kiosks and online print labs still expect JPG. A PNG of a holiday photo converted at a high quality setting (90% or more) prints identically, and the smaller file uploads much faster over hotel or mobile connections.
What converting PNG to JPG keeps and loses
What you keep
- Pixel dimensions — a 4032×3024 PNG becomes a 4032×3024 JPG, with no resizing.
- All visible colour and detail, within the limits of JPG compression at the quality you choose (default 85%).
- Opaque areas exactly as they look on screen; semi-transparent edges are blended smoothly onto white rather than left with jagged fringes.
What you lose
- Transparency — every transparent or partly transparent pixel is composited onto solid white.
- Lossless fidelity: JPG discards fine detail, most visibly around sharp text and hard-edged graphics.
- 16-bit precision, if the PNG had it; the output is 8 bits per channel.
- PNG text chunks, gamma data, any embedded ICC profile and any eXIf data — Pixohub does not copy metadata into the JPG.
Tips for better PNG to JPG results
- Use 90–95% quality for screenshots containing text and 75–85% for ordinary photos; below about 70% blocking becomes visible in skies and skin.
- If you need a coloured background instead of white behind a transparent logo, place it on that colour in an editor first, then convert.
- Converting a flat-colour logo to JPG rarely saves much and adds artifacts — keep those as PNG or try PNG to WebP.