About PNG → JPG
What about transparency?
JPG can't store transparency. verto detects an alpha channel and fills transparent areas with white before encoding, so the JPG renders correctly everywhere. The file row shows a warning so you're never surprised.
How much smaller will the JPG be?
It depends on the content. Photographs typically shrink by 5–15× when going from PNG to JPG at quality 85. Flat graphics with sharp edges (logos, screenshots) sometimes look worse as JPG — consider WebP for those.
Quality slider — what's the right value?
Quality 85 is a sweet spot for photos: visually indistinguishable from the source, but with very small files. Drop to 70–75 for thumbnails. Push to 95+ only when you need to re-edit the file later.