PNG to JPG

It disappears. JPG stores three color channels and nothing else, so the tool paints transparent regions onto a white background before encoding. If you need the see-through areas kept, stay with PNG or pick WEBP as the export format instead.

High, at 92%. Text edges are exactly where JPG artifacts show first, and Medium can leave faint smudges around small fonts. For photos of people or scenery, Medium is usually indistinguishable and roughly half the size.

Almost always for screenshots and photos, often by 80 to 95 percent. Tiny icons or images under a few kilobytes may barely change, because JPG's overhead eats the savings at that scale.

Not fully. The JPG encoder discards fine detail permanently, so converting back gives you a lossless wrapper around already-degraded pixels. Keep the original PNG if there's any chance you'll edit it later.

Yes. Bulk mode kicks in automatically when you drop multiple files, each one is processed in sequence, and the whole set arrives as one ZIP. Your machine's memory is the only real ceiling.

That's JPG's 8 by 8 block compression showing itself, and it gets worse at lower settings. Bump the preset to High or use the fine-tune slider around 90% and the blocks become invisible at normal zoom.

Completely. Decoding and re-encoding both happen in your browser through the Canvas API, so screenshots full of internal dashboards or customer data never touch a server.