PNG vs JPG: When to Use Each Format (With Examples)
The Core Difference: How Each Format Handles Compression
PNG and JPG are not interchangeable. They solve different problems. JPG (or JPEG) uses lossy compression, which means it shrinks file sizes by permanently throwing away pixel data. Each time you save a JPG, an algorithm scans for similar-colored pixels, groups them, and averages them out. You get a smaller file, but you risk visible artifacts if you push the compression too far. In Photoshop, a quality setting of 80 (File > Export > Export As) can get you a 60–70% size reduction with almost no visible loss on photos. But if you drop that quality to 40, you’ll see blocky squares—called macroblocking—especially around high-contrast areas like text on a background. PNG is the opposite: it uses lossless compression. Every single pixel is preserved, exactly as it was. The DEFLATE compression algorithm simply finds repeating patterns in the data and stores them more efficiently without discarding anything. Open a PNG, save it, open it again—the pixels are identical. This makes PNG the only choice when perfect fidelity is non-negotiable. Here’s the practical upshot: a 4000×3000 photo of a mountain landscape might be 3–5 MB as a high-quality JPG. As a PNG, that same image could balloon to 25–40 MB. For a photograph, that extra size buys you practically no visible benefit. But take a 1200×800 screenshot of a spreadsheet. As a JPG, even at quality 75, the text will be smeared and you'll see color fringing around cell borders. As a PNG, it stays perfectly sharp and might only be 300–500 KB. Your format choice should always be a deliberate decision based on the content, not just a habit.
When JPG Is the Right Call
JPG was built for photographs, and that's still its home turf. The format’s lossy compression cleverly exploits a quirk of human vision: our eyes are much more sensitive to changes in brightness than to subtle shifts in color. Photographs are filled with gradual tonal changes—a sky fading from deep blue to pale, or skin tones shifting in soft light. JPG compresses these areas aggressively, and most of the time, we don't even notice. Reach for JPG for: **Camera photos for the web.** Think product shots on an e-commerce site, hero images on a blog, or your vacation photos on Instagram. At a quality setting of 75–85, a typical DSLR photo will shrink to under 500 KB while looking identical to the original at normal screen sizes. **Any image where file size is the top priority.** This includes email attachments, images embedded in PDFs for distribution, and thumbnails. Google's PageSpeed guidelines recommend keeping images under 200 KB if you can. For photos, JPG is the fastest way to get there. **Images that are truly final.** Because JPG compression is lossy, every save cycle degrades the file. If you're working on an image iteratively, you're just asking for trouble if you keep re-saving it as a JPG. Keep your master file in a lossless format (like PNG, TIFF, or a camera's raw format) and only export to JPG as the absolute final step. The big, non-negotiable limitation of JPG is transparency. It doesn't support it. If you need to put a product shot on different colored backgrounds, JPG is not the tool for the job. You'll have to use PNG or WebP.
When PNG Is the Right Call
PNG shines exactly where JPG stumbles, thanks to its lossless compression and full transparency support. **Screenshots and screen recordings exported as stills.** Anyone who has tried to read blurry text in a tutorial screenshot knows the pain of using JPG for the wrong job. Text on a screen is high-contrast and sharp-edged. JPG compression butchers it, creating color fringing and blurriness even at high quality settings. A screenshot of a code editor, a UI mockup, or a financial dashboard must be a PNG. **Logos, icons, and illustrations with flat colors.** If you have a company logo that needs to sit on top of different colored backgrounds, you need a transparent PNG. Exporting a vector illustration from Illustrator (File > Export > Export As > PNG) preserves every crisp line. The same export as a JPG would force a white background and create fuzzy edges. **Images destined for further editing.** If you're handing a file off to a designer who needs to composite, mask, or adjust it, send a PNG. Its lossless nature means no quality is lost as the file is opened and saved across different programs. **Images with large areas of solid color.** Infographics, charts, and diagrams are perfect for PNG. The DEFLATE compression algorithm is incredibly efficient at handling large, repeating blocks of a single color. In these cases, a PNG can sometimes be even smaller than a JPG, while looking infinitely better. So what's the catch with PNG? File size, but only for photographic content. A 24-bit PNG of a detailed photo will almost always be much larger than a good JPG with no visible difference in quality. For photos, that extra size is rarely worth it.
Side-by-Side Examples With Real Numbers
Abstract comparisons are one thing, but numbers make the trade-offs real. Let's look at three concrete examples with actual file sizes. **Example 1: Product photograph (2400×1600 px, camera photo of running shoes)** - JPG at quality 85: 487 KB — clean, no visible artifacts - JPG at quality 60: 198 KB — slight softness in texture, but fine for a thumbnail - PNG (24-bit): 6.2 MB — identical to the original, but 12 times larger than the quality-85 JPG Verdict: JPG wins decisively. The PNG offers no visual benefit and would be a disaster for page load times. **Example 2: UI screenshot (1440×900 px, web browser with text-heavy page)** - JPG at quality 85: 312 KB — noticeable color fringing around black text, especially smaller fonts - JPG at quality 95: 890 KB — fringing is reduced but still visible on 12px body text - PNG (24-bit): 418 KB — perfectly sharp text, zero artifacts Verdict: PNG is the clear winner. It's actually smaller than the highest-quality JPG and looks far better. **Example 3: Company logo (800×400 px, flat design with transparent background)** - JPG at quality 90: 45 KB — forces a white background, no transparency; edges are soft - PNG (24-bit with alpha): 38 KB — perfect transparency, crisp edges Verdict: No contest. The PNG is smaller and the only format that can actually do the job, since JPG doesn't support transparency. These numbers will vary with image content, but the patterns you see here hold true for thousands of real-world files.
Converting Between PNG and JPG: What to Expect
Let's clear up a common misconception: converting a JPG to a PNG does not magically recover lost data. If a photo was saved as a JPG at quality 70, its data is gone forever. Converting that file to PNG just gives you a perfect, lossless copy of an already-damaged image. You've preserved the artifacts, not removed them. The file gets much larger, but it doesn't get any better. Converting from PNG to JPG, however, is a common and useful step when you're moving a photograph from editing to final delivery on the web. This is where you apply the JPG compression for the first time, giving you control over the final quality. CocoConvert's PNG-to-JPG converter, for instance, lets you pick a quality level from 1 to 100. I find quality 82 is a great starting point for most photos. When would you convert a JPG to a PNG? It's rare, but there are scenarios. Maybe you need to add a transparent background to an existing photo (though you'll need another tool for the masking itself). Or perhaps you're archiving old photos and want to halt any further degradation. Just remember that the compression damage from the original JPG save is already baked in. Where a tool like CocoConvert really becomes a time-saver is with batch conversions. If you have 200 PNG product photos from a designer and need to get them onto a website, converting them all to JPG at quality 80 in one go is a lifesaver. CocoConvert's batch upload handles 50 files on the free plan and 500 on Pro. It won't watch a folder or provide an API, though; for that level of automation, you'd need to look at ImageMagick scripts or a service like Cloudinary.
What About WebP, AVIF, and Other Modern Formats?
PNG and JPG have ruled the web for over two decades, but their reign is being challenged. WebP, developed by Google, is now supported by all major browsers (Chrome, Firefox, Safari 14+, Edge). It's a flexible format with both lossy and lossless modes. In its lossy mode, a WebP file is typically 25–35% smaller than a JPG of equivalent visual quality. In lossless mode, it's often 20–30% smaller than a PNG. AVIF is even newer and pushes compression further, often creating files 40–50% smaller than JPG. It's based on the AV1 video codec and also handles HDR content beautifully. Browser support is now solid across the board (Chrome 85+, Firefox 93+, Safari 16+), but the encoding process is slower and the tooling isn't quite as mature. So why are we still so focused on PNG and JPG? First, universal compatibility. JPG and PNG work *everywhere*, including ancient email clients and offline software. Second, familiarity. Most clients and vendors expect JPG or PNG and might not even know what to do with a WebP file. And finally, many professional workflows, from stock photo sites to print-on-demand services, are still built exclusively around JPG and PNG uploads. CocoConvert supports converting to and from WebP, which is a great feature. My advice: if you're building a modern web project and control the full technology stack, consider using WebP as your delivery format while keeping your master source files as high-quality JPGs or PNGs. AVIF conversion is on CocoConvert's roadmap but isn't available yet.
A Practical Decision Framework
Okay, that was a lot of technical detail. Let's boil it all down to a simple decision-making process that covers most situations. **First, look at your content:** - Is it a photograph or a photorealistic image? → Use JPG, unless you must have transparency. - Is it a screenshot, diagram, logo, or illustration with sharp lines? → Use PNG. - Does it absolutely require a transparent background? → Use PNG (or WebP for browser-only use). **Next, consider the destination:** - Web page where speed is critical? → JPG at quality 75–85 for photos; PNG for graphics; consider WebP if supported. - Print or long-term archival? → PNG or TIFF. Never use JPG for a file you plan to re-edit. - Email attachment? → JPG for photos (try to keep it under 1 MB); PNG for screenshots. - Social media? → JPG for photos (they'll recompress it anyway); PNG for any graphic with text. **And please, try to avoid these common mistakes:** - Saving a logo as a JPG and wondering why it's blurry. - Using huge PNGs for all your website photos and wondering why the site is so slow. - Converting a low-quality JPG to a PNG and expecting it to look better. - Cranking JPG quality below 70 and being surprised by the blocky artifacts on sharp edges. If you're ever truly stuck, here’s the tie-breaker: export one of each, open them, and zoom in to 100%. Look at the sharpest part of the image. If the JPG looks clean, you're good to go. If you see fuzziness or weird colors, you need PNG. A tool like CocoConvert's converter handles the mechanical part of switching formats perfectly. What it can't do is make the strategic decision for you. That requires knowing what your image is and where it's going. This framework should make that call a lot more straightforward.