PNG vs JPG: What's the Actual Difference (And Which to Use)
PNG and JPG solve different problems, not the same problem with different quality levels. Picking the wrong one for the job is one of the most common and easily avoidable mistakes when preparing images for the web.
The Core Difference: Compression Type
JPG uses lossy compression — it permanently discards some image data to shrink file size, and reapplying compression (re-saving repeatedly) degrades quality further each time. PNG uses lossless compression — no image data is discarded, so quality stays identical no matter how many times you re-save it. This single difference explains almost every practical decision below.
When PNG Is the Right Choice
PNG is built for images with sharp edges, flat colors, and text: logos, icons, screenshots, graphics with transparent backgrounds, and diagrams. Because it's lossless, small text and clean lines stay crisp instead of picking up the blurry artifacts JPG introduces around hard edges. PNG is also the only one of the two that supports true transparency (an alpha channel), which matters for logos placed over colored backgrounds.
When JPG Is the Right Choice
JPG is built for photographs — images with continuous color gradients, complex lighting, and natural textures. Photos compress dramatically smaller as JPG than as PNG with no visible quality loss at reasonable settings, because the lossy algorithm is specifically tuned for how the human eye perceives photographic detail. Using PNG for photos routinely produces files 3-5x larger for no visible quality benefit.
The Mistake: Using PNG for Everything "To Be Safe"
A common instinct is to default to PNG because it's "higher quality," but for photographic content this just means unnecessarily large files that slow down page load — which directly affects both user experience and Google's Core Web Vitals ranking factors. The right format depends on the content of the image, not a general assumption that lossless always wins.
The Mistake: Re-saving JPGs Repeatedly
Every time a JPG is opened, edited, and re-saved as JPG, another round of lossy compression is applied on top of the last one — this compounding effect is called generation loss, and it's why a photo edited and re-exported several times can look noticeably worse than the original. If you're editing a photo multiple times, work from the original file or a lossless format, and only export to JPG once at the end.
What About File Size in Practice
For a typical photo, a well-compressed JPG at 80-85% quality is usually indistinguishable from the original to the eye while being a fraction of the file size of the same image as PNG. For a logo or icon, PNG file sizes are already small because flat-color graphics compress efficiently even losslessly — so there's rarely a size penalty for choosing PNG when it's the right format for the content.
Compressing Either Format Without Losing Visible Quality
Whichever format is correct for your image, the file is often larger than it needs to be straight out of a camera or design tool. Our Image Compressor reduces JPG, PNG, and WebP file sizes directly in your browser, adjustable by a quality slider so you can find the point where file size drops without visible quality loss.
A Quick Decision Rule
If the image has text, sharp lines, flat colors, or needs a transparent background — use PNG. If the image is a photograph with natural colors and gradients — use JPG. That single question resolves the format choice correctly in the large majority of real cases.
Handling Both Formats for Free
Compressing, converting, and preparing images in either format doesn't require paid software. Browse the full list of free tools on NOVA FREETOOLS for image utilities that handle this without any cost.
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