JPG, PNG, WEBP, and SVG: what actually separates these formats
One idea explains almost every difference between image formats: whether saving the file throws data away permanently, or keeps every pixel intact.
Every image format makes the same basic trade-off differently: how much visual detail to keep versus how small the file gets. Once that one idea clicks — lossy compression throws data away permanently, lossless compression doesn't — the rest of the JPG/PNG/WEBP/SVG question mostly answers itself.
Lossy vs Lossless: The Concept Behind Everything Else
Lossless compression (PNG, SVG) shrinks a file without discarding any actual image data — decompress it and you get back exactly what you started with. Lossy compression (JPG, and WEBP in its default mode) achieves much smaller files by permanently throwing away detail the eye is least likely to notice. That trade produces dramatically smaller files, but it's a one-way street: once that detail is gone, no amount of re-saving brings it back.
Why Re-Saving a JPEG Over and Over Quietly Ruins It
This is called generation loss, and it's the most common way people accidentally degrade an image without realizing it: opening a JPEG, making a small edit, and saving as JPEG again — repeatedly — compounds the data loss each time, since every save re-applies lossy compression on top of the last round's already-degraded data.
Try it — simulate generation loss
PNG and SVG never do this — because they're lossless, saving a PNG one hundred times produces the exact same pixels as saving it once. If a file will be edited more than once, keeping it in a lossless format until the very last export avoids this compounding loss entirely.
Transparency: Why PNG (Not JPG) for Logos
JPG has no concept of transparency at all — every pixel must have some color, which is why a logo saved as JPG always shows up with an ugly white or colored box around it. PNG supports a genuine transparent (alpha) channel, which is exactly why it became the standard for logos, icons, and any graphic meant to sit on top of a different background.
Where WEBP and SVG Actually Fit In
WEBP is a newer format built to beat JPG and PNG at their own games — it supports both lossy mode (smaller than JPG at similar quality) and lossless mode (smaller than PNG, with transparency support), which is why many modern websites serve WEBP by default. SVG is a different kind of format entirely: instead of storing pixels, it stores mathematical shapes, which is why a logo saved as SVG stays perfectly sharp at any size — a phone icon and a billboard version can be the exact same file.
At a glance
| Format | Compression | Transparency | Best for |
|---|---|---|---|
| JPG | Lossy | ✕ | Photographs, complex color images |
| PNG | Lossless | ✓ | Logos, screenshots, graphics with text |
| WEBP | Both modes | ✓ (lossless mode) | Web delivery, smaller versions of either JPG or PNG |
| SVG | Lossless (vector) | ✓ | Logos and icons needing every size, perfectly sharp |
Not Sure Which Format Fits Your Image? Pick a Scenario
What are you saving?
Converting between formats is routine — a JPG to PNG converter adds a usable transparent background slot, a PNG to JPG converter shrinks a graphic for faster web delivery, and a SVG to PNG converter rasterizes a vector for platforms that require a fixed-size image.
Common Mistakes Worth Avoiding
- Repeatedly editing and re-saving the same JPEG instead of keeping a lossless working copy until the final export.
- Saving a logo as JPG and getting a white box instead of a transparent background.
- Using SVG for a real photograph — vector format can't represent photographic detail at all.
- Assuming a smaller file is always "better" without checking whether it actually still looks right at the size it'll be displayed.
Frequently Asked Questions
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One Trade-off, Four Formats
Every format on this list is answering the same question — how much detail versus how small a file — just with a different default answer. Once you know which side of that trade-off your image actually needs, picking between JPG, PNG, WEBP, and SVG stops being a guess.
