What changes when PNG becomes JPEG
PNG can store lossless colour and exact hard edges; JPEG stores a frequency approximation tuned for photographs. A photographic PNG can become much smaller, while a screenshot or logo may acquire ringing and soft coloured edges even at a high quality setting.
PNG may also carry an alpha channel. JPEG cannot. White, black, near-white, a sampled edge colour or a custom value is composited underneath before encoding, and the preview shows that choice rather than discovering it after download.
A short, inspectable workflow
- Drop one PNG file or a whole selection. The queue reads the signature inside each file instead of trusting its extension.
- Inspect the detected type, dimensions and any format notice on each row before conversion.
- Choose JPEG quality and, where transparency exists, the colour that must replace it.
- Choose whether ordinary EXIF data survives and whether GPS coordinates are removed.
- Convert the queue. Three or more finished files download as one ZIP so the browser does not open a stack of save prompts.
What the conversion cannot preserve
Lossless pixels, indexed palettes, textual chunks and alpha do not map into JPEG. Ordinary photographic EXIF can be carried when present, but PNG-specific chunks are not a general-purpose metadata contract and are not rewritten into the new file.
A converted file is a new JPEG, not the original format with a different filename. Keep the source whenever animation, layers, high bit depth, transparency or repeated future edits might matter.
Questions about this input
- Why did a transparent area turn black elsewhere?
- JPEG has no alpha channel. A converter must composite transparent pixels onto a colour before encoding; an unspecified or mishandled matte is often black. This page makes that decision explicit.
- Will PNG text and logos stay perfectly sharp?
- Not perfectly. JPEG is lossy and is poorly suited to hard high-contrast edges. Keep the PNG for logos, screenshots and line art unless file compatibility is more important than exact edges.
- Can several PNGs become one JPG?
- No. Each input becomes its own JPG. The ZIP groups downloads but does not merge image content.
Decoding and encoding both happen on this computer.