Most people use JPG and PNG interchangeably without thinking about it. That works until it doesn't — until a logo looks blurry, a screenshot has smeared text, or a photo file is inexplicably 15 MB. Here's what actually separates the two formats.
The core difference: lossy vs lossless compression
JPG (JPEG) uses lossy compression. When you save a JPG, the format permanently discards some image data to reduce file size. For photographs — rich, complex images where tiny imperfections are invisible — this is usually fine. You get a small file with no perceptible quality loss at reasonable compression settings.
PNG uses lossless compression. Every pixel is preserved exactly. The file is larger, but it's a perfect copy of the original. Save a PNG a hundred times — it still looks identical.
When to use JPG
JPG is the right choice when:
- You're working with photographs — from a phone, camera or stock image site
- File size matters and the image has lots of colour variation (photos handle JPG compression well)
- You're embedding images in a PDF and want to keep the file size reasonable
- The image will be displayed on screen at normal viewing sizes
A typical phone photo saved as JPG at 80% quality is 2–5 MB. The same image as PNG might be 15–25 MB. For PDF conversion, JPG images produce far smaller output files without any visible difference.
When to use PNG
PNG is the better choice when:
- You're working with logos, icons or graphics with flat colours and sharp edges
- The image has a transparent background (JPG doesn't support transparency)
- You're screenshotting text or UI — lossy compression smudges the crisp edges of characters
- You need to edit and resave the image repeatedly (each JPG save degrades quality slightly; PNG doesn't)
- Pixel accuracy is critical — charts, diagrams, QR codes
What about converting to PDF?
Our JPG to PDF converter handles both JPG and PNG files. Here's a practical guide:
- Photos going into a PDF → JPG. Smaller files, identical appearance.
- Logos or screenshots going into a PDF → PNG. Preserves sharp edges and transparency.
- Mixing types → fine. Our converter handles multiple formats in a single conversion.
Quick reference
- Photo from camera or phone → JPG
- Logo or icon (especially with transparency) → PNG
- Screenshot of text or UI → PNG
- Chart or diagram → PNG
- Image being embedded in a PDF for emailing → JPG
- Image being edited repeatedly → PNG