Why turn PNGs into JPGs?
PNG stores every pixel exactly, which makes photos saved as PNG very large. Many upload forms, email providers and websites have size limits, and some only accept JPG. Converting photos to JPG cuts the size dramatically while looking the same at normal viewing size.
When to keep PNG
Not every PNG should become a JPG. Keep PNG for screenshots with text, logos, diagrams and anything with a transparent background: JPG blurs sharp edges slightly and fills transparent areas with white. For photos, JPG is the right choice.
Smaller still: WebP
If the images are going on a website, WebP is smaller than JPG at the same quality and keeps transparency. Switch the format to WebP above the drop zone, or use the JPG to WebP converter for existing JPGs.