How each format compresses
JPG uses lossy DCT compression tuned for human vision: it keeps brightness detail we notice and discards color detail we barely perceive. The result is tiny photographic files — and irreversible data loss, controlled by the quality setting.
PNG uses lossless DEFLATE compression: it finds patterns and redundancy without discarding anything, so every pixel survives exactly. WebP offers both modes — lossy (VP8-based, more efficient than JPG) and lossless — plus modern features like animation and alpha.
Transparency: who supports it
PNG supports full alpha transparency, from clean cutouts to soft shadows — the reason logos and overlays live as PNGs. WebP matches it with its own alpha channel, at smaller file sizes.
JPG has no transparency at all: transparent pixels become a solid color on conversion, typically white or black depending on the tool. This single fact rules out JPG for any graphic where transparency matters.
Color, text, and sharp edges
Photographs — smooth gradients, natural textures — are JPG and WebP territory; their compression was literally designed for this content. Sharp graphics with flat colors, crisp text, and hard edges belong to PNG (or lossless WebP), where lossy compression would smear edges into halos.
Screenshots sit in between: mostly sharp text and UI, occasionally photographic content. PNG is the safe default; WebP at high quality is the lean alternative. Low-quality JPG is the classic screenshot-ruiner.
Compatibility landscape
JPG opens everywhere — every browser, every phone, every piece of software from the last 25 years. It is the format of last resort when compatibility is uncertain.
PNG is nearly as universal for viewing. WebP is supported by all modern browsers and most current software, but truly old systems may not display it. For web publishing in 2026, WebP is safe; for unknown recipients or legacy pipelines, JPG remains king.
Choosing in practice
The practical decision tree: photo for web → WebP (JPG if compatibility is uncertain); graphic/text/logo → PNG; transparency needed → PNG or WebP; email attachment → JPG; archive master → PNG or original RAW.
And the conversion principle: move toward efficiency (PNG photo → WebP) freely, but never expect a conversion to add quality. Formats are containers with trade-offs — the art is matching the container to the content and destination.
When stuck between two formats, convert to both and compare directly: file sizes on the cards, transparency behavior, and a full-zoom quality check. The empirical answer beats theory every time — and with live re-conversion, the experiment costs nothing but a moment of your time.
Frequently asked questions
What is the main difference between JPG and PNG?
JPG is lossy and tiny (best for photos); PNG is lossless and exact (best for graphics, text, transparency) but much larger for photographic content.
Is WebP better than both?
Technically yes for web use: smaller than JPG at equal quality, with transparency and lossless modes like PNG. Only legacy compatibility favors JPG.
Why can't JPG do transparency?
The format simply has no alpha channel — it was designed for photos, where transparency is meaningless. Use PNG or WebP for transparent graphics.
Which format should I use for screenshots?
PNG for pixel-perfect text, or WebP at high quality for smaller files. Avoid low-quality JPG — it blurs the text you need readable.