PNG is lossless, so photos and screenshots saved as PNG can be very large. JPG compresses photographic images far more aggressively, so a PNG photo often shrinks to a fraction of its size once converted. That makes this conversion useful for email attachments, upload forms with size limits, blog images and anything that needs to load quickly.
Know the trade-offs before you convert. JPG is lossy: it discards fine detail to save space, and flat graphics, logos and screenshots with sharp text can pick up faint blur or fringing around edges, and may not get much smaller at all. JPG also has no transparency, so transparent areas of your PNG are filled with white. If you need to keep a see-through background, convert to WebP instead.
Choose High for a good balance, Max when you want the least visible loss, or Low when file size matters most. The pixel dimensions never change, each file keeps its name with only the extension swapped, and no metadata or watermark is added. Everything runs in your browser, so your images are never uploaded.
Tip: for screenshots with small text, convert at Max or keep the PNG. For photographs, High is usually indistinguishable at normal viewing size, and you can try Medium to see how much smaller the file gets before the quality starts to show.
Slightly. JPG is a lossy format, so some fine detail is discarded. At High quality the difference is hard to see in photographs. Text and sharp line art show the loss more easily.
PNGs of screenshots, logos and flat colour already compress very well. JPG saves the most space on photographs.
JPG cannot store transparency, so transparent pixels become white. To keep transparency, convert to WebP or keep the PNG.
Yes. Add them all, convert once and download a single ZIP. Every file keeps its original name.
No. The conversion happens in your browser and the files never leave your device.